Most vegans are happy to list the reasons why a plant-based diet is superior. Going strictly animal-free can reduce one’s carbon footprint, cut the risk for cancer and chronic diseases, prevent animal cruelty and provide an excuse to make a really great dessert.

But one thing that’s probably not on your average vegan’s list is that this restrictive diet improves the quality of one’s poop—at least according to People for the Ethical Treatment of Animals (PETA). This week, the animal rights organization issued a call for more healthy vegans to consider becoming stool super donors (i.e., providing specimens on a regular basis) to serve the growing demand since fecal microbiotoa transplant is now considered the gold standard for treating recurrent Clostridium difficile (C. difficile) infections and other potentially life-threatening gastrointestinal illnesses. In this experimental medical procedure, stool from a healthy person is transplanted to the gut of an ailing patient either in encapsulated pill form or through a colonoscopy.

A study published in The New England Journal of Medicine found that 81 percent of patients with C. difficile who underwent transplantation made a full recovery from their illness. Research since has shown the cure rate after follow-up transplants may be even higher, as much as 90 percent.

The problem, however, is that good poop is actually pretty hard to find, and stool banks such as OpenBiome and Advancing Bio are quite possibly even more choosy than your average blood bank. PETA suggests that relying on fruits and vegetables as a main source of sustenance leads to a more diverse micriobiome, the complex ecosystem of bacteria freeloading inside your gut and nearly every part of your body. Many—or if one is lucky, most—are beneficial to health. Some of these microbes are even necessary for normal human functioning.

More and more research suggests that people with greater microbiome diversity tend to be healthier. Scientists have identified a link between certain gut bacteria profiles and just about every chronic medical condition, from ulcerative colitis and autism to common allergies, depression and certain cancers. More research needs to be conducted, which is another reason why people with healthy microbiomes are in high demand.

“Vegan kitchens save 100 animals a year, and now vegan bathrooms can be used to save some of our fellow human beings,” PETA President Ingrid Newkirk said in a press statement. “PETA is betting the farm that after meat-eaters experience the health and mood benefits of vegan stool, they’ll go vegan themselves.”

Fecal transplantation isn’t yet approved by the U.S. Food and Drug Administration. However, because it has been shown to be so effective for C. difficile, the FDA allows physicians to use it under their “enforcement discretion guidelines” for patients with C. difficile infections who do not respond to standard therapies. This essentially means the FDA won’t go after doctors who performs a fecal transplant once they have their patient’s consent. Last year, the FDA moved to tighten regulations by limiting the procedure only to large hospitals. 

Zain Kassam, chief medical officer of OpenBiome, is a little skeptical of PETA’s recommendation. Diet certainly has something to do with the quality of one’s stool, but it’s not the primary deciding factor when he’s determining if their poop warrants super-donor status. “Whether you’re a 34-year old vegan lawyer who loves lentils or a 22-year old college student who craves a good hamburger—OpenBiome welcomes all healthy donors in the fight against C. difficile,” he tells Newsweek. 

OpenBiome, sometimes called the “Red Cross of poop,” recruits and screens stool donors, and then it filters and freezes the raw material for clinicians to use. A large list of factors go into deciding who is qualified to be a super donor, and Kassam says the research is ongoing to gain more insight about the medicinal magic of human waste.

“For the treatment of C. difficile, our studies and others suggest that all healthy donors are super donors,” he says. “For other diseases, such as ulcerative colitis, a type of inflammatory bowel disease, preliminary research suggests there may be certain donors that seem to work best. But, the jury is still out on what makes one donor work and another not.”

In 2015, he conducted a study that proved just how hard it is to find suitable donors. Out of a pool of 459 people, only 27 actually passed clinical assessments and were permitted to submit stool samples for more extensive analysis. A study Kassam conducted the following year examined the diets of OpenBiome donors and compared it with the average diet of almost 5,000 Americans. The people at PETA will probably be disappointed to learn their findings: “Beyond a small increase in fiber, the diet of OpenBiome stool donors is largely the same as the average American.”