NEW YORK (CBSNewYork/CNN) — Doctors on Staten Island say a man suffering for years from a medical mystery has been diagnosed with an extremely rare condition that many thought was a myth — his own body was brewing alcohol and getting him drunk.

According to a team of physicians at Richmond University Medical Center, the North Carolina had been accused of driving drunk back in 2014. Despite insisting he never had a drink, police didn’t believe his story and a blood alcohol test taken at a local hospital also found the driver to be 2.5 times over the legal limit.

After years and years of medical testing, it turns out that antibiotics the patient received to treat a thumb injury in 2011 reportedly began to change to body chemistry.

The findings, which were reported in a study in BMJ Open Gastroenterology, revealed the North Carolina resident had a rarely diagnosed medical condition called “auto-brewery syndrome” (ABS) — also known as gut fermentation syndrome.

After first seeking treatment in Ohio the patient, whose name was not revealed, traveled to New York in 2017 where doctors at Richmond University discovered the man had been telling the truth the whole time. There was yeast in his gut that was likely converting carbohydrates in the food he ate into alcohol.

In other words, his body was brewing beer.

“These patients have the exact same implications of alcoholism: the smell, the breath, drowsiness, gait changes,” Fahad Malik, the study’s lead author, told CNN. “They will present as someone who’s intoxicated by alcohol, but the only difference here is that these patients can be treated by antifungal medications.”

The man was almost successfully treated at the Ohio clinic in 2015 and was told to stick to a strict carbohydrate-free diet along with some special supplements. After a few weeks however, his symptoms started to flare up again. This time, no treatment seemed to work despite visits to numerous medical professionals.

Richmond University Medical Center said in the study that they believed the antibiotics he took years ago altered his gut microbiome and allowed fungi to grow in his gastrointestinal tract.

They used anti-fungal therapies and probiotics to help normalize the bacteria in his gut, a treatment that he has continued.

“Approximately 1.5 years later, he remains asymptomatic and has resumed his previous lifestyle, including eating a normal diet while still checking his breath alcohol levels sporadically,” the authors wrote in the study.

There have only been a few studies documenting cases of gut fermentation syndrome and the condition is rarely diagnosed, Malik said. In the past, it’s even been regarded as a myth.

There have been a handful of reported cases in recent years. A 2013 study described a case of a 61-year-old man who for years seemed to be drunk all the time before he was diagnosed with gut fermentation syndrome. In 2015, a woman in upstate New York had a DUI dismissed after presenting evidence that she had the condition.

Early signs of gut fermentation syndrome can include mood changes, delirium and brain fog, the researchers wrote, even before a patient starts exhibiting symptoms of alcohol inebriation.

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