What it had to solve
Fecal microbiota transplantation works, and oral FMT drugs are in trials, but Japan had no way to collect donor stool. 'Elite' donors who pass strict screening are extremely rare, and the public did not know donating stool was even possible.
The idea
Japan's first 'stool donation' drive: coin kenben after blood donation, open a donation center, and reward donors so FMT medicine gets its raw material.
How it works
With Dentsu as branding partner, Metagen opened Japan's first stool donation center in Tsuruoka in April 2025, coined 'kenben' (stool donation) on the blood-donation model, and in November launched the Stool Donation Project: free gut-microbiome tests worth 20,000 yen for 500 applicants, and up to 60,000 yen for 800g of accepted donations.
What it did
The campaign site and project film made poop donation legible; Canon Marketing Japan invested in February 2026; the project became a Creative Innovation finalist at the ACC Tokyo Creativity Awards 2026. The pipeline advanced: an ulcerative colitis therapy in advanced medicine B, plus cancer and Parkinson's trials.
Background
Metagen Therapeutics, a Tsuruoka-based startup founded in 2020 out of Juntendo, Keio and Institute of Science Tokyo research, is developing drugs from gut bacteria. Its raw material is the stool of healthy people whose gut microbiomes pass strict screening — donors the company's CEO calls 'elite poop,' so rare that the entire supply for Japan's first fecal microbiota transplantation (FMT) pipeline depended on persuading strangers to donate.
Rather than run a medical recruitment ad, the company and Dentsu built a donation category. Japan already had a 75-year-old script for giving part of yourself to strangers: blood donation, kenketsu. Metagen borrowed its grammar, coined kenben ('stool donation'), opened the Tsuruoka Stool Donation Center in April 2025 as Japan's first such facility, and framed donors as partners in a shared health project rather than suppliers of waste.
The public-facing layer arrived in November 2025 as the Stool Donation Project (Unchi Agerou — 'let's gift poop'): a campaign site explaining the four steps to becoming a donor, a project film, free gut-microbiome tests worth 20,000 yen for the first 500 applicants, and tiered thank-you payments up to 60,000 yen for 800g of accepted donations. The framing worked on investors too — it answered what Dentsu's creative director Ryo Sasaki called the '100-yen problem,' in which Japanese biotechs get priced uniformly at IPO because their value is too abstract to judge.
Why it lands
Scarcity was the binding constraint: FMT needs screened healthy stool, qualifying donors are rare, and nobody knew donation existed — so the obstacle was awareness, not science.
Borrowing blood donation's vocabulary let people fit a strange act into a familiar moral script, lowering the disgust barrier that would sink a plain medical appeal.
Paying for tests and donations positions donors as partners in research rather than a resource, matching the company's 'health spreads from healthy people' story.
For a biotech facing uniform '100-yen' IPO valuations, a legible public brand doubled as investor relations: it made an abstract pipeline concrete.
What you can take
When the raw material is strangers' goodwill, brand the ask after a ritual people trust. Blood donation made giving part of you normal; kenben copies that grammar for waste.
Since then
The Tsuruoka center kept collecting, and legitimacy kept accruing. In February 2026 Canon Marketing Japan invested in Metagen Therapeutics through its CVC arm, citing the donation center as Japan's first, and joined a Tsuruoka City food-and-microbiome data initiative. The project was named a Creative Innovation finalist at the 66th ACC Tokyo Creativity Awards. Clinically, the oral FMT drug for ulcerative colitis won an AMED grant, with trials running for cancer and Parkinson's disease.
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