Man’s Weird Reaction to Antibiotics Has His Guts Brewing Alcohol

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A week into his course of cephalexin, a common antibiotic prescribed to ward off infection in an injured thumb, a man checked into the emergency room with some strange symptoms.

They included memory loss, brain fog, and episodes of depression, along with personality changes and uncharacteristic aggression.


Doctors were unable to get to the root of the cause, and he suffered those same symptoms for some time. Three years later, a psychiatrist treated him with antidepressants, but his issues persisted.

Things came to a head when he was pulled over on suspicion of drink driving, and was found to have a blood-alcohol level of 200mg/dL (about the equivalent of 7-10 drinks, depending on your weight). He was nauseous, vomiting, impaired, had no memory of the event, and passed out in the hospital.


The patient, however, insisted he had not had one single drink.

It was his aunt who brought him a breathalyzer, and as he tracked his measurements over time, he received similar readings.

A doctor in Ohio administered a carbohydrate test, where the patient consumes carbohydrates and then has their blood-alcohol levels monitored over the course of several hours, and found elevated alcohol levels in his blood. They also found brewer’s yeast in his stool, and eventually diagnosed him with auto-brewery syndrome (ABS).


The syndrome, also known as gut fermentation syndrome, is extremely rare. It causes the digestive system to produce ethanol that makes you intoxicated. Several cases have been reported over the years, usually discovered under similar circumstances (people arrested for drunk driving without having a drink).

This man, however, is the first documented case of ABS stemming from a course of antibiotics.

“We postulate that the antibiotic altered his gut microbiome, allowing fungal growth. This diagnosis should be considered in any patient with positive manifestations of alcohol toxicity who denies alcohol ingestion.”


He was given antifungal medications and, despite a relapse after a night of pizza and soda, is doing well.

I’m not saying this will work if you ever find yourself on the wrong end of a traffic stop, but I mean. It could be your guts making beer, and you just don’t know it.