Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

Rare Auto-Brewery Syndrome Makes Sober People Drunk

Dear Doctor: I heard about a guy who tested as drunk but hadn’t had any alcohol. Is that really even possible, or is it some kind of urban legend?

Dear Reader: It certainly sounds like the product of an overactive imagination, but the scenario you’re referring to did happen. According to news reports, a young Chinese man who had moved to Australia to attend college suddenly started getting drunk. The catch was that he swore he hadn’t imbibed any alcohol. Upon returning home to China, the breathalyzer tests he took during subsequent episodes showed a blood alcohol level up to 10 times the legal limit.

In 2014, he became gravely ill and was admitted to the hospital, 10 years after the onset of the mysterious episodes. He was diagnosed with fatty liver disease, in which a buildup of fat in the liver causes inflammation that leads to organ damage. The condition is common in people with chronic alcohol abuse, which outstrips the liver’s ability to manage and clear the resulting toxins from the body.

The Chinese man was eventually diagnosed with auto-brewery syndrome, a rare condition in which the carbohydrates that a person eats or drinks are fermented in the gut and turn into ethanol, also known as grain alcohol. As it turns out, the young man wasn’t drinking alcohol, but he was drinking a lot of fruit juice and eating carbohydrate-rich foods, thus giving the rogue microbrewery in his gut plenty of raw material to work with.

While this case is interesting on its own, it also holds promise for people with nonalcoholic fatty liver disease, or NAFLD. As the name suggests, this is a type of fatty liver disease that occurs in the absence of heavy alcohol use. In NAFLD, inflammation and cell damage can be severe enough to result in fibrosis and scarring, and can even lead to cirrhosis or liver cancer. The cause of NAFLD isn’t known. But recent studies have found that the guts of people with NAFLD were far more likely to contain certain alcohol-producing bacteria than the guts of healthy individuals. This not only opens new avenues of research, but also offers hope for an eventual cure.

(Send your questions to, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)