Can gut bacteria make you drunk? New research explains rare 'auto-brewery syndrome'

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By Olivia Bowthorpe

Gut bacteria may be responsible for alcohol intoxication in people who have not been drinking, according to new research that sheds light on the biological basis of auto-brewery syndrome, a rare and often disputed condition.

The condition, known as ABS, can sound implausible, and patients can face serious social, medical and legal consequences before being diagnosed.

It happens when microbes in the gut ferment carbohydrates into ethanol, which is absorbed into the bloodstream. This occurs on a small scale in everyone, but is amplified in those with ABS, leading to raised blood alcohol levels and symptoms of intoxication.

In the new study, published in Nature Microbiology, researchers found that specific gut microbes and metabolic pathways appear to trigger excess internal alcohol production in people with ABS, helping to explain the symptoms.

They analysed stool samples from 22 patients with ABS and 21 household partners without the condition. During flares, those with ABS produced significantly more ethanol, with levels falling after antibiotic treatment.