A similar process to the one breweries use to make alcohol can happen inside our bodies urbancow/Getty

A woman who urinates alcohol without having consumed any is the first person to be diagnosed with “urinary auto-brewery syndrome”. The condition is caused by yeast in the bladder, which ferments the sugar in urine to produce alcohol.

The 61-year-old, who has requested anonymity, has diabetes and liver cirrhosis, and was recommended a liver transplant. But repeated tests found alcohol in her urine.

Even though the woman denied drinking any alcohol, she was taken off the waiting list for a donor organ, and was instead referred for treatment for alcohol abuse, says Kenichi Tamama at the University of Pittsburgh Medical Center Presbyterian Hospital in Pennsylvania, where the woman later moved.


Doctors there again found alcohol in her urine, but further tests revealed that there was no alcohol in her blood. Stumped, the doctors asked Tamama, a pathologist at the hospital, to investigate. As Tamama conducted some basic tests, he found that the woman’s urine contained yeast.

Bladder brewery

“That’s not unusual,” he says. But because the woman’s poorly controlled diabetes meant that she had a lot of sugar in her urine, Tamama wondered if the yeast might be fermenting this sugar to produce alcohol.

To find out, he separated portions of urine that contained lots of yeast and portions with barely any yeast in them. He also added a compound that blocks fermentation to some of the batches, before leaving them all in the lab overnight.

“Even before the incubation, we noticed the alcohol smell of the specimen,” says Tamama. “The next day, the smell had intensified.”

In the urine with high amounts of yeast, the alcohol level had increased from 40 to 800 milligrams per decilitre. Considering that the test used by the hospital detects alcohol at concentrations of 20 mg/dL, that is an extreme amount, says Tamama.

Samples of urine with very little yeast, or the added compound that stops fermentation, didn’t show the same hike in alcohol content.

“The doctors were surprised and shocked,” he says. But the woman herself is relieved, he says. “Initially, clinicians thought the patient was not honest about disclosing her alcohol usage,” he says. “This alcohol thing has been haunting her.”

This case is different to other reports of “auto-brewery syndrome”, in which yeast in the gut appears to produce alcohol that is absorbed into the bloodstream. Individuals with this syndrome have high levels of alcohol in their blood, and they can experience debilitating mental fogginess along with other symptoms.

Not so rare?

Tamama and his colleagues call the woman’s condition “urinary auto-brewery syndrome”. Because the alcohol isn’t in her blood, she doesn’t feel its effects. An attempt to treat her condition with an antifungal drug failed to work, but that might not matter so much because it isn’t affecting her health, says Tamama.

“It is fascinating that it can happen in the bladder as well,” says Fahad Malik at the University of Alabama at Birmingham. After he published a report on the condition, he received between 40 and 50 emails per day from people who thought they might also have it.

“Initially I thought it was a very rare condition,” says Malik. “But the more I reach out to people, the more I realise that a lot of people probably have it and are not diagnosed.”

Journal reference: Annals of Internal Medicine, DOI: 10.7326/L19-0797