The woman was arrested while driving with a blood-alcohol level more than four times the legal limit in New York state. (Stock image)

A woman in America has escaped a drink-driving charge because she suffers from a rare condition known as auto-brewery syndrome.

The drink-driving charges were dismissed based on an unusual defence: her body is a brewery.

The woman was arrested while driving with a blood-alcohol level more than four times the legal limit in New York state. She then discovered she had a rare condition called "auto-brewery syndrome", in which her digestive system converts ordinary food into alcohol, according to her lawyer, Joseph Marusak.

A town judge in the Buffalo suburb of Hamburg dismissed the drink-drive charges this month, after Mr Marusak presented medical research showing the woman had a previously undiagnosed condition in which yeast in her intestines fermented carbohydrate into alcohol.

The rare condition, also known as gut fermentation syndrome, was first documented in the 1970s in Japan, and medical and legal experts in the US say it is being used more frequently in drink-driving cases.

"At first glance, it seems like a get-out-of-jail-free card," said Jonathan Turley, a law professor at George Washington University. "But it's not that easy. Courts tend to be sceptical of such claims. You have to be able to document the syndrome through recognised testing."

The condition was first documented in the US by Barbara Cordell of Panola College in Texas, who published a case study in 2013 of a 61-year-old man who had been experiencing episodes of debilitating drunkenness without drinking alcohol.

Mr Marusak contacted Ms Cordell for help with his client who insisted she hadn't had more than three drinks in the six hours before she was pulled over for erratic driving in 2014.

"At the end of the day, she had a blood-alcohol content of .36 without drinking any alcoholic beverages," he said. He added the woman also bought a Breathalyser and blew into it every night for 18 days, registering around .20 every time.

The legal threshold for drunkenness in New York is 0.08. Mr Marusak submitted medical evidence of his client's condition to the judge, who dismissed the drink-driving charges. The woman is now free to drive without restrictions

Christopher Belling, Assistant Erie County District Attorney, said the matter was being reviewed and his office did not comment on open cases.

Mr Marusak declined to name the woman, citing medical confidentiality laws. He said the case had been sealed since the charges were dropped.

The 'Buffalo News' described her as a 35-year-old school teacher, and quoted the arresting officer as saying she had bloodshot eyes, slurred speech, and failed several field sobriety tests.

Irish Independent