In the Yunnan province of southwestern China — home to roughly 40% of the world's wild mushroom species — there is a mushroom that has been sold openly in markets and served in restaurants for decades. Locals prize it for its rich, umami flavor. They also know something about it that visitors often learn the hard way: if you don't cook it long enough, you will start seeing tiny people.
The mushroom is called Lanmaoa asiatica, known locally as "jian shou qing" — roughly translated as "turns blue in the hand," a reference to how it rapidly changes color when touched. It's closely related to the common porcini. It is also the only known mushroom with significant culinary popularity that reliably causes hallucinations when undercooked. Every summer, hundreds of people show up at hospitals in Yunnan reporting the same experience: small, elf-like figures jumping, dancing, marching under doors, scaling walls, and clinging to furniture. Hospital records show that 96% of patients who sought treatment after eating this mushroom reported seeing "little people."
Scientists call this phenomenon "lilliputian hallucinations" — named after the miniature inhabitants of Jonathan Swift's Gulliver's Travels. It's a recognized clinical syndrome, but an extremely rare one. What makes Lanmaoa asiatica so unusual is that it appears to cause this specific type of hallucination with near-total consistency across different people, different cultures, and different countries. Most hallucinogenic substances produce experiences that vary wildly between individuals based on mindset, setting, and personal psychology. The little people are different. They show up for almost everyone.
The same hallucination has been documented in the Philippines, where an indigenous community in the remote Northern Cordillera has long known of a local mushroom that occasionally causes people to see what they call the "ansisit" — their word for little people. Genetic testing confirmed the mushroom was the same species. Cases have also been reported in Papua New Guinea. A Daoist text from the 3rd century CE describes a "flesh spirit mushroom" that, if consumed raw, allows the eater to "see a little person" — suggesting this mushroom, and its specific effect, may have been known in China for nearly two thousand years.
What the mushroom is doing neurologically remains genuinely unknown. Researchers have confirmed that the active compound is not psilocybin — the chemical responsible for the effects of recreational "magic mushrooms." Chemical analysis has identified numerous compounds in Lanmaoa asiatica, but as of 2025, none of them have been linked to the hallucinations. The mechanism is a complete mystery. Whatever is triggering these visions is something science hasn't catalogued yet.
The timeline of the experience adds to what makes it so strange. Hallucinations don't begin immediately — they typically start 12 to 24 hours after ingestion, and can last for up to three days. This delay makes the mushroom impractical as a recreational drug — no culture appears to use it intentionally as a psychedelic — and it makes the experience particularly disorienting for people who didn't realize what they'd eaten. Many hospitalizations occur because people simply don't know what's happening to them.
In 2023, U.S. Treasury Secretary Janet Yellen unknowingly ate a dish containing the mushroom during an official visit to China. She reported no ill effects — the mushroom had been thoroughly cooked, which deactivates whatever compound causes the hallucinations. The incident made international news and briefly drew more public attention to Lanmaoa asiatica than decades of scientific research had managed to generate.
Researchers are now working to identify the active compound and understand how a single fungal chemical could produce such a specific, consistent visual experience across different people and cultures. If they find it, it could open new avenues for understanding brain disorders, visual processing, and the neuroscience of hallucination itself. For now, the restaurants in Yunnan just set a timer — and the server reminds you not to eat it too soon.
