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Flush: The Remarkable Science of an Unlikely Treasure
For readers of Giulia Enders’ Gut and Bill Bryson’s The Body , a surprising, witty and sparkling exploration of the teeming microbiome of possibility in human feces from microbiologist and science journalist Bryn Nelson.
The future is sh* the literal kind. For most of human history we’ve been, well, disinclined to take a closer look at our body’s natural product—the complex antihero of this story—save for gleaning some prophecy of our own health. But if we were to take more than a passing look at our poop, we would spy a veritable cornucopia of possibilities. We would see potent medicine, sustainable power, and natural fertilizer to restore the world’s depleted lands. We would spy a time capsule of evidence for understanding past lives and murderous ends. We would glimpse effective ways of measuring and improving human health from the cradle to the grave, early warnings of community outbreaks like Covid-19, and new means of identifying environmental harm—and then reversing it.
Flush is both an urgent exploration of the world’s single most squandered natural resource, and a cri de coeur (or cri de colon?) for the vast, hidden value in our “waste.” Award-winning journalist and microbiologist Bryn Nelson, PhD, leads readers through the colon and beyond with infectious enthusiasm, helping to usher in a necessary mental shift that could restore our balance with the rest of the planet and save us from ourselves. Unlocking poop’s enormous potential will require us to overcome our shame and disgust and embrace our role as the producers and architects of a more circular economy in which lowly byproducts become our species’ salvation. Locked within you is a medicine cabinet, a biogas pipeline, a glass of drinking water, a mound of fuel briquettes; it’s time to open the doors (carefully!). A dose of medicine, a glass of water, a gallon of rocket fuel, an acre of sometimes hope arrives in surprising packages.
The future is sh* the literal kind. For most of human history we’ve been, well, disinclined to take a closer look at our body’s natural product—the complex antihero of this story—save for gleaning some prophecy of our own health. But if we were to take more than a passing look at our poop, we would spy a veritable cornucopia of possibilities. We would see potent medicine, sustainable power, and natural fertilizer to restore the world’s depleted lands. We would spy a time capsule of evidence for understanding past lives and murderous ends. We would glimpse effective ways of measuring and improving human health from the cradle to the grave, early warnings of community outbreaks like Covid-19, and new means of identifying environmental harm—and then reversing it.
Flush is both an urgent exploration of the world’s single most squandered natural resource, and a cri de coeur (or cri de colon?) for the vast, hidden value in our “waste.” Award-winning journalist and microbiologist Bryn Nelson, PhD, leads readers through the colon and beyond with infectious enthusiasm, helping to usher in a necessary mental shift that could restore our balance with the rest of the planet and save us from ourselves. Unlocking poop’s enormous potential will require us to overcome our shame and disgust and embrace our role as the producers and architects of a more circular economy in which lowly byproducts become our species’ salvation. Locked within you is a medicine cabinet, a biogas pipeline, a glass of drinking water, a mound of fuel briquettes; it’s time to open the doors (carefully!). A dose of medicine, a glass of water, a gallon of rocket fuel, an acre of sometimes hope arrives in surprising packages.
432 pages, Hardcover
Published September 13, 2022
44 people are currently reading
2609 people want to read
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Displaying 1 - 30 of 44 reviews
August 22, 2022
While I generally tear through books, it took me quite awhile to read Flush by Bryn Nelson. It is extremely well-written- combining historical facts, humor, and current/future “poop” medical use and research. It is bursting with so much information that there were many times I needed to put it down and give my brain a little time to absorb it all. Shorter chapters may have made it a breezier read, yet it is highly worth your time.
I learned a lot more than I thought I would, including a whealth of information on the miracle of fecal transplants, how covid (temporarily) ruined forward momentum on research application, and how the heck humans began to think of a natural and healthy body function as taboo and disgusting.
This is fascinating stuff. I’m not sure if I’ll find many patrons who wish to discuss it with me, solely due to its topic. However, I literally read parts out loud to my husband (who would not have chosen this as a topic he wanted to learn more about) and we had some lively chats about it. I can’t wait to find more people who want to discuss this book!
My thanks to NetGalley and Grand Central Publishing for access to a digital ARC.
I learned a lot more than I thought I would, including a whealth of information on the miracle of fecal transplants, how covid (temporarily) ruined forward momentum on research application, and how the heck humans began to think of a natural and healthy body function as taboo and disgusting.
This is fascinating stuff. I’m not sure if I’ll find many patrons who wish to discuss it with me, solely due to its topic. However, I literally read parts out loud to my husband (who would not have chosen this as a topic he wanted to learn more about) and we had some lively chats about it. I can’t wait to find more people who want to discuss this book!
My thanks to NetGalley and Grand Central Publishing for access to a digital ARC.
March 13, 2023
Flush dives deep and makes a strong case for using what comes naturally as the natural resource it is instead of flushing it all away. As noted by others, maybe too detailed at times, but a fascinating book about the most mundane, taboo, and universal of topics.
January 17, 2023
3.5 stars - I found the first half of the book more engaging than the second.
February 22, 2023
A grown-up book about poop, from the revulsion it causes and why, its uses in criminology, anthropology and epidemiology, as a C. diff and IBS treatment, its contribution to greenhouse gas emissions and how to go about recycling, composting and turning it into fuel with alternative wastewater management. I will refrain from making any puns, there are enough of them in the book.
November 20, 2025
3.5. Very interesting premise — how we can reframe our relationship with waste to have a more sustainable future. But it was a slog to read: repetitive, many examples with sometimes little connections between, jumping back and forth from topics. But overall learned a lot so would recommend.
February 14, 2024
Loved it. Easy, fun, over the top read. Can't wait to share poopstories ar book club
September 24, 2022
Very gee whiz. It often felt like a credulous journalist repeating marketing material, instead of skeptically digging deeper. Scattershot and repetitive. Mostly innumerate, as, e.g., in this quote:
> If the world captured and repurposed its collective output, the theoretical value of human-derived biogas alone could be worth up to US$9.5 billion annually
> If the world captured and repurposed its collective output, the theoretical value of human-derived biogas alone could be worth up to US$9.5 billion annually
December 24, 2022
There's a lot of interesting stuff in this book, but I really struggled getting into it and staying with it. It was a slog of a read. Still, if you're interested at all in the topic, it's very much worth the slog.
December 29, 2023
I think what makes this book so interesting is that it the chapters at the beginning all about what our poop actually is, how we make it, and how we came to learn all of these things are relate back in the later chapters in the book when conversations about how to use solid waste at a large-scale, industrial-scale uses of our poop. This was such a fascinating read on how we digest things, the colonies of bacteria inside of our gut that process the variety of things our food is made out of, and how that solid waste can be used to help grow food and even produce carbon-neutral energy.
I think the most interesting chapter for me was the conversation around wastewater conversion to potable drinking water. Again, at the beginning of the book it discusses why we're so poop-averse in the first place (evolutionary brain wiring that poop=diseases) and this comes up again when Nelson interviews people who use treated waste water to make beer or even use treated solid waste to make fertilizer. My understanding of the water cycle got completely turned upside down in the chapter specifically about wastewater. After the Big Bang and the initial creation of all the elements that eventually were bound together to create Earth and all the molecules that it's made out of, it's not like the Earth naturally regenerates any of the water humans drink or use. We've been cycling through the same water since the beginning of our planet, which then if you think about it is ALL treated wastewater. The psychological barrier of drinking water that maybe has been more immediately treated is one that the scientific community has to contend with when it comes to pushing projects that recycle water because I think that understanding of the permanence of the water cycle did it for me. I understand if it doesn't for everybody though.
The chapters on fecal matter transplants to help cure people with bacterial infections like C. Diff were also really cool. Poop transplants!!??
In all, this book was really interesting. I learned a shit ton (haha) about how our bodies create solid waste, how society has dealt with that waste historically and deals with it today, and the environmental and health impacts that more mindfully dealing with and using it can make.
I think the most interesting chapter for me was the conversation around wastewater conversion to potable drinking water. Again, at the beginning of the book it discusses why we're so poop-averse in the first place (evolutionary brain wiring that poop=diseases) and this comes up again when Nelson interviews people who use treated waste water to make beer or even use treated solid waste to make fertilizer. My understanding of the water cycle got completely turned upside down in the chapter specifically about wastewater. After the Big Bang and the initial creation of all the elements that eventually were bound together to create Earth and all the molecules that it's made out of, it's not like the Earth naturally regenerates any of the water humans drink or use. We've been cycling through the same water since the beginning of our planet, which then if you think about it is ALL treated wastewater. The psychological barrier of drinking water that maybe has been more immediately treated is one that the scientific community has to contend with when it comes to pushing projects that recycle water because I think that understanding of the permanence of the water cycle did it for me. I understand if it doesn't for everybody though.
The chapters on fecal matter transplants to help cure people with bacterial infections like C. Diff were also really cool. Poop transplants!!??
In all, this book was really interesting. I learned a shit ton (haha) about how our bodies create solid waste, how society has dealt with that waste historically and deals with it today, and the environmental and health impacts that more mindfully dealing with and using it can make.
September 27, 2022
In his introduction to Flush: The Remarkable Science of an Unlikely Treasure, author Bryn Nelson relates a Siberian folktale that tells how as the First Bird (a raven) flew through the void, he would, as birds do, occasionally excrete. The more solid parts became the land (the hardest parts turned into mountains) while the more liquid parts formed rivers and lakes. It’s been a long time, then, that people have described the word as full of shit. For Nelson, though, and for that matter the Siberians, that description is less a pejorative and more an opportunity. In Flush, Nelson takes the reader on an exhaustive tour of all the ways our waste product is, well, going to waste.
Early on, Nelson gives us the biological basics on the how and what of what we flush, along with tidbits that will either fascinate the reader or make them wish for a little less detail, such as different transit times for digestible material between men and women, weight differences in the “final product” between Americans and other nations (our lack of fiber means our poop is much lighter) and how amazingly wide the range of transit time and other factors can be from individual to individual (some, perhaps many, might be more likely to mumble “TMI” when Nelson offers up his own details thanks to the trio of apps he used for a while to track his own waste product and how his diet affected the product). We also get some historical information, such as how the ancient Scythians dipped their arrowheads in a fecal slurry to infect and kill those whom the arrow didn’t kill immediately.
Once the how and what is covered, Nelson moves into why simply flushing our waste down the drain might not be the best option. What else might we do instead? Well, we could use it for fecal transplants, which have been shown to decisively help treat irritable bowel syndrome and c-diff infection (the later a major health issue that kills many Americans annually and which fecal transplant has been shown to cure at a stunning 94 percent rate). Nelson does an excellent job of showing the long, difficult road it took to get FTs accepted (believe it or not, the first recorded one took place in 4th century China), with individuals performing their own at-home ones via online tutorials until the medical establishment finally caught up.
Another medical reason we might want to pay more attention to our poop is for diagnostic purposes. For individuals to some extent, but more importantly, Nelson details how various communities have turned to wastewater examination as a means of learning what illnesses are circulating and also where to best, most effectively target resources.
In other sections, Nelson explores non-medical applications, using our waste as “bio-solid” fertilizer, turning into transport or cooking fuels, using to detoxify contaminated land, and even turning it into potable water. The last is not speculative tech – reclaiming waste into water has been done on the International Space Station for years and a number of cities have turned to doing the same. As one might imagine, the concept turns a lot of people off (a significant minority say they would never drink such water). But psychologists have found that if the reclaimed water is added to natural water sources, such as reservoirs or rivers, the public is far more accepting of the idea, considering the “tainted” water is “cleansed” by the natural water.
Nor is it just our current waste that is useful. Nelson also points to how anthropologists, historians, and archaeologists are mining old, even fossilized (called “coprolites”), waste for a ton of information to reconstruct ancient illnesses and diets. This is such a recent usage that one scientists is quoted by Nelson explaining how they thought such material was so useless they used to have contests with it to see how far they could throw it in daily games of “Frisbee throwing.”
As noted, the book is thorough; it’s hard to imagine that Nelson left anything out in terms of possible applications and for the most part, it’s all fascinating (one of the most unexpected and interesting elements is a discussion of huma gut bacteria being threatened with extinction and attempts to use the waste of hunter-gatherer societies to “replenish” the evolutionary well). Possibly Nelson might be a bit too thorough in spots, with the details threatening to overwhelm some readers. And as mentioned above, if not overwhelming in terms of data, some readers might wish for a little less personal info. But mileage will certainly vary on both of those, and I’m willing to guess that anyone who picks up a book about shit is willing to go a pretty good distance with the author.
If I had one complaint, it would be that at times I wanted Nelson to offer up a bit more of the counter-arguments, a little more explanation of how much is still in the prototype/non-scaled stage. For instance, biosolid fertilizer has been called into question as to its safety, and at one point Nelson refers to the impact on serotonin and thus depression, but more recent research has questioned that linkage.
But in the end, the positives greatly outweigh any issues, which are both few in number and minor in impact. The depth of information and the fluidity of its delivery, combined with Nelson’s conversational tone and willingness to place himself in the midst, along with its relatively unusual subject matter, make Flush a strong example of popular science. Anyone who tells you differently is full of, well, you know.
Early on, Nelson gives us the biological basics on the how and what of what we flush, along with tidbits that will either fascinate the reader or make them wish for a little less detail, such as different transit times for digestible material between men and women, weight differences in the “final product” between Americans and other nations (our lack of fiber means our poop is much lighter) and how amazingly wide the range of transit time and other factors can be from individual to individual (some, perhaps many, might be more likely to mumble “TMI” when Nelson offers up his own details thanks to the trio of apps he used for a while to track his own waste product and how his diet affected the product). We also get some historical information, such as how the ancient Scythians dipped their arrowheads in a fecal slurry to infect and kill those whom the arrow didn’t kill immediately.
Once the how and what is covered, Nelson moves into why simply flushing our waste down the drain might not be the best option. What else might we do instead? Well, we could use it for fecal transplants, which have been shown to decisively help treat irritable bowel syndrome and c-diff infection (the later a major health issue that kills many Americans annually and which fecal transplant has been shown to cure at a stunning 94 percent rate). Nelson does an excellent job of showing the long, difficult road it took to get FTs accepted (believe it or not, the first recorded one took place in 4th century China), with individuals performing their own at-home ones via online tutorials until the medical establishment finally caught up.
Another medical reason we might want to pay more attention to our poop is for diagnostic purposes. For individuals to some extent, but more importantly, Nelson details how various communities have turned to wastewater examination as a means of learning what illnesses are circulating and also where to best, most effectively target resources.
In other sections, Nelson explores non-medical applications, using our waste as “bio-solid” fertilizer, turning into transport or cooking fuels, using to detoxify contaminated land, and even turning it into potable water. The last is not speculative tech – reclaiming waste into water has been done on the International Space Station for years and a number of cities have turned to doing the same. As one might imagine, the concept turns a lot of people off (a significant minority say they would never drink such water). But psychologists have found that if the reclaimed water is added to natural water sources, such as reservoirs or rivers, the public is far more accepting of the idea, considering the “tainted” water is “cleansed” by the natural water.
Nor is it just our current waste that is useful. Nelson also points to how anthropologists, historians, and archaeologists are mining old, even fossilized (called “coprolites”), waste for a ton of information to reconstruct ancient illnesses and diets. This is such a recent usage that one scientists is quoted by Nelson explaining how they thought such material was so useless they used to have contests with it to see how far they could throw it in daily games of “Frisbee throwing.”
As noted, the book is thorough; it’s hard to imagine that Nelson left anything out in terms of possible applications and for the most part, it’s all fascinating (one of the most unexpected and interesting elements is a discussion of huma gut bacteria being threatened with extinction and attempts to use the waste of hunter-gatherer societies to “replenish” the evolutionary well). Possibly Nelson might be a bit too thorough in spots, with the details threatening to overwhelm some readers. And as mentioned above, if not overwhelming in terms of data, some readers might wish for a little less personal info. But mileage will certainly vary on both of those, and I’m willing to guess that anyone who picks up a book about shit is willing to go a pretty good distance with the author.
If I had one complaint, it would be that at times I wanted Nelson to offer up a bit more of the counter-arguments, a little more explanation of how much is still in the prototype/non-scaled stage. For instance, biosolid fertilizer has been called into question as to its safety, and at one point Nelson refers to the impact on serotonin and thus depression, but more recent research has questioned that linkage.
But in the end, the positives greatly outweigh any issues, which are both few in number and minor in impact. The depth of information and the fluidity of its delivery, combined with Nelson’s conversational tone and willingness to place himself in the midst, along with its relatively unusual subject matter, make Flush a strong example of popular science. Anyone who tells you differently is full of, well, you know.
February 2, 2023
Bit surprised at how interesting book was. I suspected it may be one of those books that I dropped in and out of but there was enough to keep me going.(boom, boom) Did make me wish I had retained more knowledge on chemical reactions not that you need it.
Now conducting a very, unscientific, experiment to ascertain how disgusting folks find the subject matter. My wife will not even touch the book! Some medical friends at least knew about FMT, you can read about it. Not too surprised to find that gardeners are the most intrigued.
Well worth a read.
Now conducting a very, unscientific, experiment to ascertain how disgusting folks find the subject matter. My wife will not even touch the book! Some medical friends at least knew about FMT, you can read about it. Not too surprised to find that gardeners are the most intrigued.
Well worth a read.
November 17, 2022
Everything you ever wanted to know, and some things you didn’t , about poops place in our lives. Some chapters deal with our bodies and how to have the healthiest relationship with waste and others deal with ideas like composting toilets, recycling poop info water and fuel and the possibility of using it for food during space travel. Both scientific and humorous, a great read
Read
January 5, 2023DNF'ing. Feels like every two paragraphs the book switches to a new topic, or the author suddenly switches back to an old topic with barely any connection to the previous sentence. I was really excited for this one from the description but it's almost impossible to read. Frustrating.
November 24, 2023
" There is no guano comparable in fertility to the detritus of a capital. A great city is the most powerful of dung producers. To employ the city to enrich the plain would be a sure success. If our gold is manure, on the other, our manure is gold. What is done with this gold, manure? It is swept into the abyss." from Les Miserables, 1867
This book caught my eye in the new books section, and written in the same spirit as the Les Miserables quote above. The book begins with the stomach, small intestine and our microbiome. He even goes as far as to talking about sending his stool sample into a company like uBiome to map out his microbiome and even talks about fecal matter transplants (Eww!). Microbiome studies give us clues about our diet and those with a more diverse microbiome have less chance of developing diabetes, obesity, depression and age better. ( https://www.nytimes.com/2021/10/13/we...)
If that grosses you out, the book quickly pans out towards the societal concerns with poop. Nelson recounts the impact in WW1 and the harvesting of "white gold" (the nitrogen rich poop from colonies of pelicans, boobies and cormorants that dined on nitrogen-packed fish), which was replaced by Friz Haber and Carl Bosch's technological triumph process to create rich fertilizer (for making food... or explosives).
Nelson carries his enthusiasm towards many modern advances at sewage treatment plants around the world, ranging from the common practice of turning waste water into renewable energy (methane), via anaerobic digestion, to topics such as harvesting gold sewage water. Sewage treatment plants have advanced their ability to recovery resources (energy, nutrients, recycled water), in 2014 they were officially reminted by the Water Environment Federation as "Water Resource Recovery Facilities" instead of Sewage treatment plants.
Nelson casts a wide net in covering the latest advancements in the field including:
-Monitoring of WW for Covid, and explores how the initial studies were done at student dorms and can be expanded to detect people who are addicted to opioids before it is too late.
-San Lorenzo, CA (Right in my backyard) Ora Loma Sanitary districts ambitious experiment of creating a "horizontal levee", a dual purpose level that protects against storm surges using vegetation on a slope, but also helps further process waste water.
-The Norwegian Cambi process (Now being using at San Fancisco's South East Plant), that can extract more renewable energy out of the sludge, and further process that can turn it into jet fuel that only has a 25% cost premium.
-Compost toilets in Africa (where their high fiber diets create twice as dense poop) that are leading an agricultural revolution.
Nelson's book is for anyone interested in the message that we must become comfortable with what's inside us to realize its full potential for the planet. However sitting at 300 pages the book can come across as overwhelming for those unlike me who don't work in the environmental sector.
This book caught my eye in the new books section, and written in the same spirit as the Les Miserables quote above. The book begins with the stomach, small intestine and our microbiome. He even goes as far as to talking about sending his stool sample into a company like uBiome to map out his microbiome and even talks about fecal matter transplants (Eww!). Microbiome studies give us clues about our diet and those with a more diverse microbiome have less chance of developing diabetes, obesity, depression and age better. ( https://www.nytimes.com/2021/10/13/we...)
If that grosses you out, the book quickly pans out towards the societal concerns with poop. Nelson recounts the impact in WW1 and the harvesting of "white gold" (the nitrogen rich poop from colonies of pelicans, boobies and cormorants that dined on nitrogen-packed fish), which was replaced by Friz Haber and Carl Bosch's technological triumph process to create rich fertilizer (for making food... or explosives).
Nelson carries his enthusiasm towards many modern advances at sewage treatment plants around the world, ranging from the common practice of turning waste water into renewable energy (methane), via anaerobic digestion, to topics such as harvesting gold sewage water. Sewage treatment plants have advanced their ability to recovery resources (energy, nutrients, recycled water), in 2014 they were officially reminted by the Water Environment Federation as "Water Resource Recovery Facilities" instead of Sewage treatment plants.
Nelson casts a wide net in covering the latest advancements in the field including:
-Monitoring of WW for Covid, and explores how the initial studies were done at student dorms and can be expanded to detect people who are addicted to opioids before it is too late.
-San Lorenzo, CA (Right in my backyard) Ora Loma Sanitary districts ambitious experiment of creating a "horizontal levee", a dual purpose level that protects against storm surges using vegetation on a slope, but also helps further process waste water.
-The Norwegian Cambi process (Now being using at San Fancisco's South East Plant), that can extract more renewable energy out of the sludge, and further process that can turn it into jet fuel that only has a 25% cost premium.
-Compost toilets in Africa (where their high fiber diets create twice as dense poop) that are leading an agricultural revolution.
Nelson's book is for anyone interested in the message that we must become comfortable with what's inside us to realize its full potential for the planet. However sitting at 300 pages the book can come across as overwhelming for those unlike me who don't work in the environmental sector.
August 24, 2022
My thanks to both NetGalley and the publisher Grand Central Publishing for an advanced copy of this new book on the many uses and science behind the waste that we leave behind..
I grew up in a time when certain things were not just brought up in polite conversation, they were never even a part of any conversation. Procreation probably lead the never discussed subject list, intoxication was mentioned about certain members of the family, never our own. Defecation maybe when sick, but even in jest it was a subject that was considered, well for others, or maybe HBO comedy specials. As I got older I began to notice the health of guts and everything that went in or out was becoming more conversational, but still it was not a subject I wanted to share. Thankfully Bryn Nelson, PhD has no problems with discussing the subject in every way shape and form. Flush: The Remarkable Science of an Unlikely Treasure is an examination of what according to the children's book everybody does, along with the science and knowledge that can be gained both for ourselves and the environment.
The book begins well at the beginning, answering the age old question of what a bear does in the woods. Turns out the giant short- faced bear ate plenty of plants and animals, which relieving itself helped the growth of plants and trees in North America through the natural fertilizer over 20,000 years ago. The book then focuses on humans and the science and biology involved in breaking down what we eat, what this shows of our health and where said wastes go. There is a large interest in human waste as it can tell the health of a city, seeing what diseases or even COVID traces, tracking the higher breakout areas and allocating resources based on what they find. One of the big problems with the study of human waste is getting past the shame and disgust that humans feel for their own bodies a lot of the time. The benefits, however, seem to outweigh these feelings of human taboo, and that is also discussed.
The writing is very good taking a subject that is not one that people like to discuss and makes it interesting and the reader left wanting to know more. The balance of humor to science I think helps a lot. Get ready for Dad jokes is my only warning. Nelson has a, I hate to say, good feel for th subject, and even in sections that readers might think, echh, has the ability to make it both interesting and educational. The science on the environment and disease was fascinating I feel that I have more of an interest in a subject that I never gave much thought about.
Recommended for fans of Mary Roach or Bill Bryson's latest book on the human body. The writing is very good and will leave the reader fairly flushed at the end. I kid. I enjoyed this far more than I thought I would, and found that I have more or an appreciation for all the little things our bodies do for us everyday.
I grew up in a time when certain things were not just brought up in polite conversation, they were never even a part of any conversation. Procreation probably lead the never discussed subject list, intoxication was mentioned about certain members of the family, never our own. Defecation maybe when sick, but even in jest it was a subject that was considered, well for others, or maybe HBO comedy specials. As I got older I began to notice the health of guts and everything that went in or out was becoming more conversational, but still it was not a subject I wanted to share. Thankfully Bryn Nelson, PhD has no problems with discussing the subject in every way shape and form. Flush: The Remarkable Science of an Unlikely Treasure is an examination of what according to the children's book everybody does, along with the science and knowledge that can be gained both for ourselves and the environment.
The book begins well at the beginning, answering the age old question of what a bear does in the woods. Turns out the giant short- faced bear ate plenty of plants and animals, which relieving itself helped the growth of plants and trees in North America through the natural fertilizer over 20,000 years ago. The book then focuses on humans and the science and biology involved in breaking down what we eat, what this shows of our health and where said wastes go. There is a large interest in human waste as it can tell the health of a city, seeing what diseases or even COVID traces, tracking the higher breakout areas and allocating resources based on what they find. One of the big problems with the study of human waste is getting past the shame and disgust that humans feel for their own bodies a lot of the time. The benefits, however, seem to outweigh these feelings of human taboo, and that is also discussed.
The writing is very good taking a subject that is not one that people like to discuss and makes it interesting and the reader left wanting to know more. The balance of humor to science I think helps a lot. Get ready for Dad jokes is my only warning. Nelson has a, I hate to say, good feel for th subject, and even in sections that readers might think, echh, has the ability to make it both interesting and educational. The science on the environment and disease was fascinating I feel that I have more of an interest in a subject that I never gave much thought about.
Recommended for fans of Mary Roach or Bill Bryson's latest book on the human body. The writing is very good and will leave the reader fairly flushed at the end. I kid. I enjoyed this far more than I thought I would, and found that I have more or an appreciation for all the little things our bodies do for us everyday.
July 20, 2024
This is an important topic, but the book is written in a gee-whiz journalistic style, so it's not my cup of tea. For a 400-page book on a narrow topic, there were bizarre omissions (like Sulabh). Also, it seemed like the author was repeating catchy ideas from other sources without really digging into them, like the story that Sanitarians made cholera and such worse because they were fighting filth instead of working with Germ Theory--the facts contradict that conclusion even in the abbreviated version told in this book. The author does a lot of speculation and a lot of veering off into tangents about psychology, politics, evolution, etc.
Alternatively:
Flushed: How the Plumber Saved Civilization
The Origins of Human Disease
The Great Filth: The War Against Disease in Victorian England
Good Germs, Bad Germs: Health and Survival in a Bacterial World
I Contain Multitudes: The Microbes Within Us and a Grander View of Life
Alternatively:
Flushed: How the Plumber Saved Civilization
The Origins of Human Disease
The Great Filth: The War Against Disease in Victorian England
Good Germs, Bad Germs: Health and Survival in a Bacterial World
I Contain Multitudes: The Microbes Within Us and a Grander View of Life
June 9, 2023
Good topic and quite a few interesting angles for everyone to ponder regarding the value of the things culture norm has deemed waste. Having read a decent amount of space opera, I am fully aware of the importance of recycling. On a spaceship, everyone is eating and drinking everyone else's pee and poop. Why should it be different on Earth, which essentially is just another spaceship hurling around the Sun, albeit a lot lot bigger.
Perspective and cultural norm are frequently the downfall of human kind and obstacle of progress. Living on such a giant generation ship, we lose sight of the fact that the Earth can fail. The so-called yuck factor is nothing but irrational reflex groomed by generations of misunderstanding. I will give the past generations a pass, because they were not equipped to know better. But I can never forgive those nowadays, with all that they can know, who still push back against recycling our shits just because of the "yuck factor".
It's quite sad to realize that humans in the ancient time definitely reused their shit for fertilizer or what not; humans in the distant future exploring the galaxy will definitely recycle their shit as feeds to their next meal. It is only humans now, today, who shy away from one of the most natural products we produce. The sheer stupidity and irony is mind-boggling.
Back to the book. To cut to the chase, I think it is too long. Some central topics are repeated several times with a lot of journalist-padding. Some pages are off topic (e.g. the quite extensive mention of the body farm. I know what the author was trying to do there, but a few paragraphs shall suffice, not several pages). And too many names. It's hard to keep track of the researchers/entrepreneurs/activists after a while, especially when they appear across different chapters and their affiliations only mentioned once scores of pages ago. I gave up trying to follow who is whom after a while.
Perspective and cultural norm are frequently the downfall of human kind and obstacle of progress. Living on such a giant generation ship, we lose sight of the fact that the Earth can fail. The so-called yuck factor is nothing but irrational reflex groomed by generations of misunderstanding. I will give the past generations a pass, because they were not equipped to know better. But I can never forgive those nowadays, with all that they can know, who still push back against recycling our shits just because of the "yuck factor".
It's quite sad to realize that humans in the ancient time definitely reused their shit for fertilizer or what not; humans in the distant future exploring the galaxy will definitely recycle their shit as feeds to their next meal. It is only humans now, today, who shy away from one of the most natural products we produce. The sheer stupidity and irony is mind-boggling.
Back to the book. To cut to the chase, I think it is too long. Some central topics are repeated several times with a lot of journalist-padding. Some pages are off topic (e.g. the quite extensive mention of the body farm. I know what the author was trying to do there, but a few paragraphs shall suffice, not several pages). And too many names. It's hard to keep track of the researchers/entrepreneurs/activists after a while, especially when they appear across different chapters and their affiliations only mentioned once scores of pages ago. I gave up trying to follow who is whom after a while.
February 18, 2023
A bear craps in the wood. Do we care, no..we celebrate!
The "yuck!", factor is high for all of us, but Bryn Nelson penetrates our fears of miasma, effluvi and do-do. The future is poop! And the good news, the future is here. FMT therapies for C-difficile, Waste monitoring for pandemics. Biopsies of pre-industrial tribes to map the microbiota for optimal digestion.
There are moment in history that our collective boom-boom has lead to serious problems. Consider the Paris edicts of the 16th century for guidance on chamber pot disposal. Consider the "Great Stink" of the Thames in England, and the sewage overflows that lead to a national plumbing infrastructure. Facing climate challenges of freshwater and fossil fuel depletion, we may find a spark in our bark. Our fears are not unfounded, parasites, worms, and disease has always been associated with poop. But we are finding ways to clean, and dispose of the human waste without losing the benefits.
Nelson begins his book with the question "what do we value". Our impulse will probably not be the pineapple size matter we release every two weeks. But poop is what binds us. When we take out the disgust, the grossness, and the sense of impurity, we may very well see the energy for engines, the fertilizer for our food production, and the genetic brown print back to our ancestor.
We learned as children - "Everybody Poops". We can learn as adults this isn't just the source of humility, but of growth, power and joy!
The "yuck!", factor is high for all of us, but Bryn Nelson penetrates our fears of miasma, effluvi and do-do. The future is poop! And the good news, the future is here. FMT therapies for C-difficile, Waste monitoring for pandemics. Biopsies of pre-industrial tribes to map the microbiota for optimal digestion.
There are moment in history that our collective boom-boom has lead to serious problems. Consider the Paris edicts of the 16th century for guidance on chamber pot disposal. Consider the "Great Stink" of the Thames in England, and the sewage overflows that lead to a national plumbing infrastructure. Facing climate challenges of freshwater and fossil fuel depletion, we may find a spark in our bark. Our fears are not unfounded, parasites, worms, and disease has always been associated with poop. But we are finding ways to clean, and dispose of the human waste without losing the benefits.
Nelson begins his book with the question "what do we value". Our impulse will probably not be the pineapple size matter we release every two weeks. But poop is what binds us. When we take out the disgust, the grossness, and the sense of impurity, we may very well see the energy for engines, the fertilizer for our food production, and the genetic brown print back to our ancestor.
We learned as children - "Everybody Poops". We can learn as adults this isn't just the source of humility, but of growth, power and joy!
September 6, 2025
This book is a fun, informative, but occasionally exhausting discussion of all things related to poop. It is written in an humorous tone and the science is explained in an accessible way, though I skimmed some sections that droned on a bit (such as the archeological discussions of the components of our ancestors' waste).
Each chapter focuses on a particular topic and could be read as a standalone essay. I particularly enjoyed the chapters about using wastewater to make beer and composting toilets. Though some sections like the one discussing fecal transplants is not for the squeemish, this book makes the case that we need to get over it because we are literally flushing away what could be a valuable resource.
Each chapter focuses on a particular topic and could be read as a standalone essay. I particularly enjoyed the chapters about using wastewater to make beer and composting toilets. Though some sections like the one discussing fecal transplants is not for the squeemish, this book makes the case that we need to get over it because we are literally flushing away what could be a valuable resource.
October 18, 2022
Occasionally icky, often fascinating and very educational, Flush: The Remarkable Science of an Unlikely Treasure by Bryn Nelson thoroughly explores the science of human waste. I learned a lot about missed opportunities to reuse our waste, learn about our health, the history of human waste and possible future technologies.
April 17, 2025
It was remarkable to learn all the beneficial uses for poop. Apparently we need to change our outlook on our distaste to mention, discuss or think about poop. The last fifty pages or so of the book was slow moving to me.
The author mentions how we reuse all the water on earth over and over again and that is all we have. Isn’t rainwater new water? Can anyone answer this question?
Just a remark- why do automatic flushing toilets continue to be in use when they seem to be the biggest abusers of wasting water when they automatically flush several times (instead of just once) when one is doing their business in the stall?
The author mentions how we reuse all the water on earth over and over again and that is all we have. Isn’t rainwater new water? Can anyone answer this question?
Just a remark- why do automatic flushing toilets continue to be in use when they seem to be the biggest abusers of wasting water when they automatically flush several times (instead of just once) when one is doing their business in the stall?
August 10, 2023
This book contains a lot of fascinating material (no pun intended!) that I had never really considered before, as well as showcasing a number of creative ways of dealing with the growing pile of poop that our ever-expanding population is producing. The author’s extensive research and expertise and his deep concern for our environment are evidenced on almost every page. It is well worth the read. But if I had one criticism, it would be that the book could have been a hundred pages shorter. Towards the end, I found I was having to force myself to read on.
December 20, 2023
With contagious enthusiasm, Nelson inspires us to get over the "yuck factor" and recognize an undervalued resource for healing our bodies and the planet. He had me giggling throughout, yet also appreciating that the applicable problems -- including deadly infections and climate change -- are not laughing matters. Flush is full of compelling examples of poop's potential, from tracking disease to fertilizing crops to fueling rockets. As Nelson notes, "Sometimes hope arrives in unexpected packages." I highly recommend this thought-provoking, fun read.
February 18, 2024
I really enjoyed this shitty book! It was written in an entertaining, yet fact-filled and scientifically laced, way that had me turning the pages, eager to see what kind of crap was on the next page. There were some chapters toward the end that dragged a little, or maybe I was just pooped out reading about poop. Overall, it was an enlightening book, one that will probably become much more impactful as the human population continues to grow and we’ll eventually all need composting toilets in every household. I shit you not.
October 6, 2022
For a book about poop written during the pandemic, Flush brings a lot of positive energy into the world. Filled with humor, riveting storytelling, and an optimistic voice, Flush blends lyricism with science to create hope. Leaving no compost pile unturned, Nelson tackles energy, agriculture, environmentalism, medicine, architecture, history, psychology, and of course, hygiene—there is a lot to digest in this book.
did-not-finish
December 8, 2022Did not finish.
Flush had some really interesting material, but it felt overly wordy. I had a hard time maintaining interest and sometimes it felt like it was all over the place.
I enjoyed the discussion regarding the morality and ickiness and why it's become taboo to talk about, but I wish it had been a little more streamlined and less wordy.
Thank you to Grand Central Publishing for the copy.
Flush had some really interesting material, but it felt overly wordy. I had a hard time maintaining interest and sometimes it felt like it was all over the place.
I enjoyed the discussion regarding the morality and ickiness and why it's become taboo to talk about, but I wish it had been a little more streamlined and less wordy.
Thank you to Grand Central Publishing for the copy.
February 2, 2023
One of the most important and impactful science books I've read in the lady decade. Yes, it's about poop. But once you get past the instinctual yuck factor, it's hard to think of many things more important to society than how we deal with it, and if we can really make the transition, slow and difficult though it may be, from thinking of it as waste to be shipped away to thinking of it as a resource to be used, a whole lot of our worst problems get easier to solve.
May 7, 2024
Wonderful! I learned so much and it really left me feeling hopeful about the future! Perhaps humanity really can find a way to live in harmony with nature. It never occurred to me that the key to our salvation would be our own feces, but this book really has me feeling that thinking about our poop differently really might be the solution to all of our problems. And to think that we have so many of the answers already! All we need is for it to catch on.
November 25, 2025
Flush by Bryn Nelson makes me want to have a composting toilet. It's not just that American infrastructure could generally use an upgrade but that it's a wasted resource. This was a very dense book that could have used a little more editing. I also don't have any background with Latin naming conventions and so I struggled to get through the chapter on gut bacteria. Like recycling our resources it's work but finishing the book was worth it!
March 28, 2023
A book about human waste, it's affect on our health and the environment, and new ways scientists are using it to help improve out lives and the life of the planet.
I was enjoying this book, but the level of detail bogged me down. Not a fault of the authors by any means -- just not where my head was at the time. I made it about 2/3 of the way through.
I was enjoying this book, but the level of detail bogged me down. Not a fault of the authors by any means -- just not where my head was at the time. I made it about 2/3 of the way through.
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