An American started producing beer in his own gut after a fungal growth produced high levels of yeast, a study has found.
It describes how the 46-year-old's rare condition was only discovered after he was pulled over by police on suspicion of drink driving.
Hospital tests showed the unnamed construction worker had a blood-alcohol level of 200 mg/dL, equivalent to consuming around 10 alcoholic drinks, although he repeatedly denied he had drunk any alcohol.
The strange symptoms of auto-brewery syndrome (ABS) are recounted by researchers in a case study published in the British Medical Journal.
In the report, the researchers reveal how a once healthy, light social drinker began experiencing all the effects of alcoholism despite becoming teetotal.
The man first began experiencing uncharacteristic episodes of depression, "brain fog" and aggressive behaviour in 2011 after taking a course of antibiotics for a thumb injury.
The true cause for his symptoms only became apparent years later, following his arrest for suspected drink driving. The study outlined how the man, after being discharged from hospital, first sought treatment at an Ohio clinic where a stool sample revealed the presence of Saccharomyces cerevisiae (also known as brewer's yeast) and a related fungus in his system.
The yeast is instrumental in beer brewing as it helps ferment carbohydrates and produces alcohol.
To confirm the ABS diagnosis, the Ohio clinic gave him a carbohydrate meal and monitored his blood alcohol levels. After eight hours, his blood alcohol level had risen to 57 mg/dl.
Despite being treated for the fungi at the clinic and being put on a strict no-carbohydrate diet - as eating carbohydrates led to him becoming inebriated - the condition flared up again after a few weeks and he had a fall while inebriated that resulted in him suffering intracranial bleeding.
While recovering in hospital, his blood alcohol spiked as high as 400 mg/dL - twice the concentration recorded when he was pulled over by police. As his symptoms got worse, he searched online for a solution and contacted the specialists at Richmond University Medical Centre in New York.
Experts used anti-fungal therapies and probiotics to treat the gut microflora. The fungal growths appear to have been completely retreated.
The researchers say ABS is "under-diagnosed" and could be a possibility in any case where someone appears to be intoxicated but denies drinking.
The Daily Telegraph UK