“With humor, insight, and intestinal fortitude, Dr. Bryn Nelson persuades us that a ‘shittier future’ will be happier, healthier, and wealthier. Flush is a fascinating read.”— Michelle Nijhuis, author of Beloved Beasts: Fighting for Life in an Age of Extinction

Bryn Nelson is a Seattle-based freelance writer and editor with an avid interest in biology, biomedicine, ecology, green technology and unconventional travel destinations. After shifting course from a career in microbiology, Bryn accumulated two decades of journalism experience and has written for more than 30 publications ranging from The New York Times to Cancer Cytopathology. Before becoming a journalist, he received his PhD in microbiology from the University of Washington.

Subsequently, Bryn received a graduate certificate in science writing from the University of California at Santa Cruz, and interned at The Californian in Salinas, California, and at Newsday in Melville, New York. In 2000, he accepted a staff position at Newsday as a member of the science desk, where he spent the next seven years writing extensively about genetics, stem cell research and cloning, evolution, ecology and conservation.

While at Newsday, Bryn was one of four principal writers on the award-winning, 13-part “Long Island: Our Natural World” series, which we converted into a field guide. He also wrote “Saving Bobby,” a multiple award-winning, 12,000-word feature about the frantic effort to save a toddler whose father had accidentally driven over his head.

Since 2007, Bryn has been a freelance writer and editor. In his spare time he enjoy photography, singing and renovating the 1906 Craftsman house where he lives with his husband, Geoff, and their energetic boxador, Piper.

His book Flush: The Remarkable Science of an Unlikely Treasure, is a surprising, witty and sparkling exploration of the teeming microbiome of possibility in human feces. 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.”

Bryn's Featured Titles

Flush: The Remarkable Science of an Unlikely Treasure

Grand Central Publishing |

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*t: 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 soil: sometimes hope arrives in surprising packages.


Don’t Pooh-Pooh Poo: What Can Poop Really Tell You About Your Health?

We tend to flush and forget. But what valuable information is swirling down the drain and what might it tell us? In this entertaining talk, Bryn Nelson explains what poop really contains, and how some simple observational aids can already tell us a lot about what’s going on inside. He discusses the high-tech future of tracking poop and the explosion of at-home tests for sequencing the gut microbiome, searching for signs of colon cancer, and monitoring other aspects of gut health. What has potential and what’s pure hype? Nelson breaks it down.

Don’t Pooh-Pooh Poo: What Can Poop Really Tell You About Your Child’s Health?

For Parents

Few things are more mysterious and frightening to new parents than baby poop. What the heck is meconium? Should you be worried about that foul-smelling mound of green in their diaper? What about functional constipation? For this talk, Bryn Nelson guides audiences through the good, the bad, and the ugly of baby poop and explores what science is teaching us about the developing gut microbiome.


Gross Science: The History and Psychology of Disgust

Poop tends to top the list of things that disgust most people, but it hasn’t always been this way. For this talk, Bryn Nelson delves into the history of our “behavioral immune system” that helps keep us safe from icky things, how disgust can sometimes work against our own best interests and environmental solutions when the emotion is overly sensitive, and how we can overcome disgust when it’s harmful and reach a better balance between protection and overreaction.

Getting Over Gross Science: How Beer and Other Tactics Are Changing Minds About the Urgent Need for Water and Soil Reclamation

For this tailored extension of the talk about disgust, Bryn Nelson explains the psychology of disgust and then discuss how successful water reclamation projects and biosolids-based fertilizers have overcome barriers rooted in the yuck factor. Free beer, bottled water, public tours, and other strategies are helping utilities win over wary people to the necessity of recycling our valuable output.


Flipping the Script: How Poop Is Driving a Range of Surprising Environmental Solutions

We tend to think of poop as an environmental nightmare. But a range of clever projects around the world are demonstrating how it might heal polluted land and water while fighting global warming. Wastewater treatment plants are rapidly reinventing themselves as resource recovery facilities, and we’re now able to extract pure water, phosphorus, ammonia, fertilizer, and energy in the form of biogas and electricity. For communities, this means transforming sanitation and environmental headaches into a source of new value, as Bryn Nelson describes in this talk of far-ranging and surprising success stories.


Dogs, Bugs, Poop, and True Crime

In this adult-geared talk, Bryn Nelson describes how poop-sniffing canines and poop-loving insects have helped sleuths crack some major criminal cases. This is gross science at its very best. Nelson explains how the cloud of chemicals we emit can provide a distinctive odor print that can be readily sniffed by dogs, and how the succession of bugs attracted to feces and bodies can help forensic pathologists estimate time of death and other crucial details that can help bring victims a measure of justice.


Dino Poo and Ancient Latrines: What Can Fossil Poop Teach Us About the Past?

Note: this talk could be tailored for kids or done as a workshop.

This talk explores how fossilized dinosaur poop, or coprolites, can tell us about the extinct animals’ favorite foods. In the same way, latrines from throughout history can tell us what our ancestors ate, how they interacted with other people, and how healthy they were. Old poop can be a surprisingly good time capsule that helps us fill in the gaps of the distant past.


Poop Ecosystems! How Bison Patties, Elephant Dung and Other Natural Deposits Support Life Around the World

Note: this talk could be tailored for kids or done as a workshop.

This talk illustrates how nature has recycled nutrients throughout history by explaining the incredibly diverse groups of plants and animals that depend upon animal poop. Bats, tapirs, elephants, whales, bison, even worms—whether on land or by sea, animals’ regular output can be lifegiving to the fauna and flora around them. In this fun and engaging talk, Bryn Nelson explains how poop can illustrate some basic concepts of ecology, like the many connections linking every form of life on Earth.


The Sewers May Save Us: The Past and Future of Wastewater Epidemiology

From polio to COVID-19, this talk delves into the fascinating world of environmental surveillance. Bryn Nelson explains how sewage treatment plants, sewers, and even airplane bathrooms can be incredibly important places to look for the initial signs of microbial diseases, well before the first patients may begin showing up to hospitals.

Our Bowels and Sewers May Save Us: The Past and Future of Fecal Transplants and Wastewater Epidemiology

This variation of the previous talk includes the colorful history and evolution of fecal transplants as an example of how an individual’s feces can save the life of someone else. From the fringes to mainstream medicine, the powerful curative may have even more applications in medicine. Bryn Nelson compares that powerful example of personal salvation with the aggregate public health good that can come from our collective output via wastewater epidemiology.


Back to the Loo-ture: Humanure, Biogas, and Compost as Catalysts for Space-Age Sustainability

Note: this talk could be easily tailored toward a more rural audience.

Some of the most advanced buildings in the world have featured seemingly out of place fixtures: composting toilets. Meanwhile, big tanks that mimic the conditions of the human gut are popping up in cities and dairy farms around the world and pumping out an environmentally friendly alternative to natural gas. What’s behind these promising trends and what can they teach us about sustainable living and farming? In this talk, Bryn Nelson explores how the deceptively simple technologies of composting biosolids and producing biogas may usher in a new era in more self-sufficient, sustainable, and environmentally conscious urban centers and rural farms.


Fifteen Affirmations for the Determinedly Optimistic

Global warming. Food insecurity. Environmental pollution. Sometimes the bad news can feel overwhelming and leave us demoralized and uncertain where to even start. In this optimistic talk, Bryn Nelson draws about the lessons learned from researching and reporting his book, Flush, to give audiences some concrete steps to take toward a more hopeful future. If you think our problems are too big to solve, and that the proposed solutions are too small to do any good, this talk may help change your mind through its exploration of what we’ve already achieved and what more we can do.

Bryn’s Science Writing

Bryn’s Medicine Writing

Bryn’s Environmental Writing

Honors, Awards & Recognition

NLGJA Award for Excellence in Opinion/Editorial Writing for “How stochastic terrorism uses disgust to incite violence,” Scientific American, 2023

Apex Grand Award for “A different kind of smart: What pathologists can learn from an octopus,” Cancer Cytopathology, 2023

Apex Grand Award for “The case for empathy,” Cancer Cytopathology, 2018

Bricker Award for Science Writing in Medicine, Honorable Mention, 2017

Apex Grand Award for “In debating the right to die, a shift in tone among physicians,” Cancer Cytopathology, 2016

National Institute for Healthcare Management (NIHCM) Foundation,
Health Care Print Journalism Award Finalist, “HM@15” Series, The Hospitalist, 2012

Association of Health Care Journalists Awards,
First Place in Large Newspapers & Wire Services Category for “Saving Bobby,” Newsday, 2007

Deadline Club Award,
Best Feature Reporting in Newspapers & Wire Services Category for “Saving Bobby,” Newsday, 2007

New York Press Club Award,
Best Web Exclusive Content, “Saving Bobby,” Newsday, 2007

Press Club of Long Island Award,
Best Online Multimedia Reporting, “Saving Bobby,” Newsday, 2007

Newsday Publisher’s Award,
Feature Reporting, “Saving Bobby,” Newsday, 2006

Press Club of Long Island Award,
Coverage of West Nile Virus, Newsday, 2005 and 2001

Newsday Publisher’s Award,
Team Enterprise Reporting, “Our Natural World” Series, Newsday, 2003


Association of Health Care Journalists (AHCJ) Member
Association of LGBTQ Journalists (NLGJA) Member
National Association of Science Writers (NASW) Member
Northwest Science Writers Association (NSWA) Member
Society of Environmental Journalists (SEJ) Member

Media Kit

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where you can download author photos and cover images.

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