Freakonomics Radio: The Power of Poop

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Photo: Janice Haney Carr, Centers for Disease Control and Prevention. An infection of the Clostridium difficile bacteria, seen through a micrograph here, causes pseudomembranous colitis and can lead to death.

The “Power of Poop”: Since the beginning of civilization, we’ve thought that human waste was worthless at best, and often dangerous. What if we were wrong?

I don’t know when most of you listen to our podcasts — probably while driving or running or hanging out at your desk. But here’s a fair warning: if you happen to listen to our podcast while eating, you might want to change your routine for at least this one episode. It’s called “The Power of Poop,” and while it’s got some mind-blowing science and stories in it, there’s also a bit of a gross-out factor. (You can download/subscribe at iTunes, get the RSS feed, listen live via the link in box at right, or read the transcript here.)

In a nutshell: throughout civilization, human feces has posed considerable health hazards; when it gets into the water supply, for instance, a lot of bad things can happen. But in recent years, a variety of medical researchers, many of them gastroenterologists, have pushed for a greater understanding of poop, and have made some startling discoveries.

To paint it with a very broad brush: it could be that many maladies — from intestinal problems to obesity to disorders like multiple sclerosis and Parkinson’s and Alzheimer’s and perhaps even cancer — are related to damaged or missing gut bacteria; the solution therefore may lie in transplanting healthy bacteria into a sick person.

How is this accomplished? (Okay, hold your nose for a moment.) A fecal transplant. Yes, you read right: taking the stool from a healthy person, mixing it with a saline solution, and injecting it into an ill person. The procedure resembles a colonoscopy; it’s a sort of combination of organ transplant and blood transfusion, which one doctor in our podcast calls a “transpoosion.”

Fecal transplants go back several decades, but momentum is unquestionably building, thanks largely to a rise in bench science looking into the bacterial environment of the gut — and that is due to the latest DNA technologies and computational techniques.

In this podcast, you’ll hear from two researcher/practitioners: Thomas Borody, a Polish-born gastroenterologist who works at the Centre for Digestive Diseases near Sydney, Australia; and Alex Khoruts, a Belarussian-born gastroengerologist and immunologist at the University of Minnesota. (Here’s one Borody paper on the topic, and here’s one from Khoruts; both are gated.) You’ll also hear from one of Borody’s patients, William Kostopoulous, who received a fecal transplant to treat his multiple sclerosis. According to both men, the treatment worked marvelously; Borody is currently setting up medical trials to try to establish proof.

William Kostopoulos, on his custom chopper, with Thomas Borody; it seems a fecal transplant helped Kostopoulos get his life back. (Photo: Zoe Arnold)

Here are some key excerpts from the Borody interview:

BORODY: Fecal matter, I was brought up to believe, was waste. But we’ve now learned that it’s the largest organ of the body. It contains about nine times more living bacteria, bacterial cells, than the body contains human cells. So, in a manner of speaking, we are 10 percent human and 90 percent poo. …

When the stool is infected with a bug, when we changed the flora by implanting another person’s stool, that other person may contain bacteria which manufacture antibiotics. And this is the key: bacteria make molecules that kill other bacteria. In fact, most antibiotics come from bacteria, such as vancomycin for example. And you will remember, fungi produced penicillin. So it now physiologically makes good sense that when you implant flora from a healthy person into a person that’s got infected flora, that infected flora may be cured by that single implantation. …

Well, the feedback is very much like Barry Marshall‘s. I was initially ostracized. There was a program on our ABC Radio where a professor of medicine named me on television as being a charlatan for doing fecal transplants and he had no idea of the science behind it, very much like those people that initially criticized Barry Marshall, and initially Louis Pasteur was also criticized like this, and so was Edward Jenner with immunization for smallpox. [N.B.: see also Ignatz Semmelweis.] So I don’t expect anything different, but even now my colleagues would avoid talking about this or meeting me at conferences, although this is changing. I’ve just had an invitation to speak at an international conference about fecal transplantation. …? So I think we might be turning a new leaf, and I think we should, with poo especially.

And, from Khoruts:

KHORUTS: Well, part of me has not overcome that feeling [of disgust with human waste]. I think it’s universal. It’s evolutionarily put in there; we’re supposed to avoid the stuff. But I also realize that what it represents is shedding of our microbial organ. So I also think about all the functions that that entity has. It’s essentially like the elephant in the room for the gastroenterologist. We talk about all the other parts of the digestive tract, but we’re so ignorant about this component that most gastroenterologists and other scientists know very little about it. So our level of knowledge hardly exceeds that of a fifth-grader who just says, exactly as you said, “Eeewww.” … We have some understanding of how complex [the microbial organ] is. We have understanding of some of the basic components. We’re done classifying about 50 percent of different species that are there. We have some idea of how this organ is inherited, transmitted generation to generation. We have some idea of differences between individual species. We have some idea about the evolution of this organ. And we’re beginning to understand some of its functions.

And from William Kostopoulos:

KOSTOPOULOS: It wasn’t an overnight occurrence where I got better in like 15 seconds. But all I know now is, I’m 47 years old, I ride a custom chopper, I travel the world, I have a great time and I’m not in the bloody wheelchair, right? That’s all I know.

It’s a fascinating prospect: that for centuries, we’ve collectively looked at human waste as nothing but a frightful by-product of our existence, a source of shame and disease. Wouldn’t it be amazing if it turned out to be a health breakthrough rather than a heath hazard?

There are other goings-on in the world of poop as well: a poop-powered car; human waste used to heat homes in Oxfordshire; might it happen in New York, too? And, thanks to Flush Tracker, residents of some countries can find out where their poop goes when it isn’t being repurposed.

Uncomfortable Sharing

Why would we want to paint poop with a very broad brush?

Robyn Ann Goldstein

simultaneity rocks


Just speculation here: could the apparent increase in disorders in the US population such as ADHD and the autism spectrum be associated with early feeding habits of infants? Are they not getting "good" intestinal bacteria with the formulas and hygenically-prepared foods?

Someday treatment will be a medication like immunization, no doubt genetically engineered, and the ick-factor far removed.


Autism is highly heritable, and its apparent increase is due to an increase in diagnosing existing cases.


This episode echoes propaganda spewed by medical quacks.
Testimonial? Check.
Post hoc fallacy? Check
Argument from ignorance? Check.
Found the cause and cure of every disease? Check.
"They laughed at Barry Marshall"? Check.
Dismissing critics? Check.

Fecal transplants are a last resort treatment for pseudomembranous colitis, not a first-line treatment for MS.
Relapsing-remitting MS is characterized by flare-ups followed by periods of remission, so any placebo taken during the flare-up will appear to work until the next relapse.

Here's a novel idea. Instead of sensationalizing fringe science, which is likely to be wrong, how about educating people about the best, most solid science.

Robyn Ann Goldstein

if fringe science is wrong, then all of science is wrong. FYI


Not all fringe science is wrong, but most of it is. Typically, it's missing a plausible mechanism and strong evidence, so it resorts to anecdotal evidence and wishful thinking (e.g. "Wouldn't it be amazing if it turned out to be a health breakthrough rather than a heath hazard?")

Mick Mills

Is it a case of ill-disciplined economics vs very disciplined evidence based medicine ?


Not just bacteria but larger organisms can help keep you healthy, apparently - there's growing interest in re-introducing hookworms to people to treat a variety of autoimmune disorders, based on the theory that helminths are not so much parasites as symbionts, and that we are healthier with them than without them. The hookworms seem to dampen the overactive immune response at the heart of autoimmune disorders.

Here's an article on a study investigating using hookworms to treat MS:


I thought this article was rather good. I walk away looking at the way traditional eastern medicine works, and it kind of resembles the principles of long term care of the GI flora. Needless to say eastern medicine is not always the answer, but it does open the question on the science yet to be written on this topic.

If great beer is made of great "ingredients", great equipment and a known cultivation of bacteria, perhaps the human "beer making" can also be improved.

All the best!


Ugliest good news

Adam Macy

Radiolab did a story on hookworms aiding in medical "cures" last year some time. I caught it on This American Life episode 404 in act 3.

Perhaps they are really on to something here.


If it works, don't knock it. Every part of us should have a purpose and if the purpose of poop is to be "transposed" into someone else, more power to you. Using poop to heal is just using the necessary resources available to us. Yea, poop is gross, but if it can save lives then use it.


The thing that most people are turned off by is the fact that it is human feces that is being dealt with. It is just a taboo. There are people who drink coffee seeped from beans picked out of poop. Even if this is not true, we should still keep an open mind to the possibilities.


I think it's too early to jump to conclusions about this research. The possibilities are there, we just need to wait and see if the results are what we hope fore.


Animals eat poop all the time...they don't seem to suffer from nearly as many chronic illnesses as we humans do...just sayin'...


Just wondering if you guys have thought about another aspect of poop - it could be turned into compost and used to enrich the earth, instead of becoming nasty sewage and allowed to muddy our waters. We compost all kinds of animal poop and use it to enrich the soil. Check out the Humanure Handbook. My family has been recycling our poop for years with great results. Think about it this way: take a 5 gallon bucket of clean drinking water. Now poop into it. Then try to clean that water up for drinking again. Why do we do this? It is crazy. People don't want to deal with their own waste, whether it be household garbage or their bodily waste but we will need to start thinking about these problems as population grows and water sources are more scarce.


Fantastic, & Surprising - on first reading/hearing ......... BUT having read it and understood the explanation, I am , as most people must , surprised that no one has come up with this before .
Well done ...... as always.

Greetings from 'poop-shy' Ireland !


I think the question we need to ask is how the bad bacteria go there in the first place.

Fecal Transplants sounds like a backward step to curing the problem; if a healthy person is eating well and obtaining the correct nutrients from the food they eat then why can't the unhealthy person do the same?!

All the nutrients we need comes from the correct intake of natural, unprocessed foods.
Fecal transplants sounds like a waste of money to me.

Michael W. McCullough, DC

It's fascinating to read the balance of intestinal flora is so critical to maintain our immune system and health, which has been known for many years. The part that was missing is "why has so many people's digestive out of balance?" This issue was lightly touched on. I firmly believe that antibiotics and a poor diet that does not include the pre-biotic fructoligosaccharides to maintain the "healthy flora" is to blame.

I realize that most researchers claim that a probiotic taken by mouth would logically be destroyed in the stomach acid before getting into the alkaline small intestine. I agree with that but there are acid resistant strains of probiotics that are available. I have been taking an acid resistant strain for many years and now at 61 years old, I have never missed a day of work due to illness. I feel like I am 40 and there are few activities that I cannot perform.

I hope the researchers keep up the good work on intestinal flora and why it is critical.