Imagine a sleek, café-like clinic tucked away in Japan’s scenic Tsuruoka City. There’s no coffee served but visitors are still leaving with a reward: ¥5,000 (about $34.50 USD) in Amazon gift cards. Their contribution? A “high-quality” poop sample. This isn’t a joke it’s the heart of Japan’s first stool donation facility, launched in April 2025 by biotech company Metagen Therapeutics, and it’s already sparking global curiosity.
The aim isn’t humor it’s health. Metagen’s new Tsuruoka Stool Donation Room, located in Tsuruoka Science Park, is part of a serious medical push: collecting gut bacteria to develop microbiome-based therapies for gastrointestinal diseases like C. difficile infections and ulcerative colitis. It’s quirky, yes but it’s also cutting-edge science.
Potential donors, aged 18–65, begin by applying through Metagen’s “Chomusubi” platform, where they undergo a strict health screening that includes medical exams at a local hospital. Only 5–10% of applicants make the cut.
“Only stool samples matching Types 4 and 5 on the Bristol Stool Chart are eligible,”
a Metagen representative shared. That means soft, well-formed stools essential for extracting usable gut bacteria.
Approved donors then visit private, specially designed restrooms in Tsuruoka’s science park. The environment is meant to feel welcoming, almost spa-like reducing discomfort and stigma.
Metagen’s goal is to isolate beneficial gut bacteria for Fecal Microbiota Transplants (FMT) and future medications. The human gut microbiome trillions of microorganisms that influence digestion, immunity, and even mental health has become one of the most exciting frontiers in medical research.
Japan sees over 1 million gastrointestinal cases annually, making the search for local, healthy microbiome donors more than just an experiment it’s a national healthcare priority.
“Gut flora diversity varies dramatically by region and diet,”
said Dr. Ayako Fujimoto, a microbiologist at Juntendo University.
“Japanese microbiota may offer unique strains not found in Western populations.”
Japan isn’t alone in monetizing poop. In the U.S., OpenBiome offered $40 per stool back in 2015 but only 4% qualified. Another American program, Human Microbes, advertises up to $500 per sample, though these are rare cases.
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Compared to these, Metagen’s ¥5,000 payout may seem modest. But donors can contribute every 2–3 months, earning up to ¥30,000 a year (~$207). It fits the donation norms many English-speaking readers are familiar with from plasma to egg donation just with a more unusual material.
Some are motivated by the money. Others, by science.
“I signed up because I thought it was a funny way to help medicine,”
said Kenji Saito, a local Tsuruoka resident.
“And hey, free Amazon gift cards!”
The city, known as a UNESCO Creative City of Gastronomy, plays a role too. The local diet rich in fermented foods and seasonal produce helps residents maintain a healthy gut, making Tsuruoka a prime location for donor sourcing.
Even the Donation Room’s interior reflects this thoughtfulness: clean, cozy, and designed to ease the process for first-time contributors.
That’s a fair question and one that Metagen anticipated.
“Every donor undergoes thorough screening to ensure privacy, health, and ethical collection,”
said Taku Nakahara, CEO of Metagen Therapeutics.
“This is not a cash-for-waste scheme. It’s a legitimate scientific program, overseen by medical professionals.”
Paying for bodily donations isn’t new blood, sperm, and egg donors have long received compensation. But stool? That’s new to most, and naturally prompts skepticism. Still, no major controversies have been reported in Japan so far.
