Your gut can make alcohol. Scientists are learning how and why

Your gut can make alcohol. Scientists are learning how and why

• Auto-brewery syndrome causes the body to produce alcohol without drinking.
• Gut microbes like E. coli can ferment sugars into alcohol, causing intoxication.
• Stool tests could aid ABS diagnosis and prevent misdiagnosis or false accusations.

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For most people, feeling drunk has a simple explanation: you had a drink. But for a small number of people around the world, alcohol can be made inside their own bodies, without a single sip. It sounds like something out of a medical oddity column, but doctors say it is real and, for those who have it, deeply frustrating.

The condition is called auto-brewery syndrome, or ABS. In simple terms, it means certain microbes in the gut start behaving like a tiny brewery. Instead of just helping digest food, they ferment sugars and turn them into alcohol.

New research reported in early 2026 adds to the evidence that some common bacteria, including E. coli and Klebsiella pneumoniae, can play a role in this. In people with ABS, this process can push blood alcohol levels high enough to cause obvious symptoms, even though they have not touched a drop.

Doctors have been writing about cases like this for years, but many patients say they were not believed at first. Some were accused of secretly drinking. Others got into trouble at work or even with the law because breath or blood tests showed alcohol in their system. The new findings help explain how that can happen.

In many cases, the problem seems to start after the gut’s normal balance is disturbed. This can happen after heavy use of antibiotics, surgery, or long-standing digestive problems. When certain microbes take over, and the person eats a lot of carbohydrates, the gut can start producing alcohol in much the same way yeast does in beer or wine.

The symptoms can vary. Some people feel lightheaded or foggy. Others slur their words, struggle to walk straight, or feel completely out of control. In a few extreme cases, doctors have measured alcohol levels that would be dangerous in someone who had been drinking.

One promising part of the new research is a better way to spot the condition. Instead of just testing breath or blood, scientists say stool tests could help identify the bacteria responsible. That could save patients from being wrongly blamed and speed up proper treatment.

Treatment usually means trying to get the gut back into balance. Doctors may use targeted antibiotics or antifungals, followed by probiotics and changes in diet. Many patients are told to cut back sharply on sugars and refined carbs.

Auto-brewery syndrome is still very rare. But it is a striking reminder that the microbes living inside us can sometimes do surprising things. In a few unlucky people, they can even turn an ordinary meal into something closer to a drink.