North Carolina police arrested a drunk driving man whose stomach prodused alcohol on his own.

Men’s blood alcohol levels were 0.2%, about 2.5 times the US limit. The man assured the police that he did not drink. Doctors eventually discovered that he was telling the truth. There were yeast in his gut that probably turned carbohydrates into alcohol.

A man has a rare condition known as bowel fermentation syndrome. This condition occurs when the yeast in the gastrointestinal tract causes the body to convert the carbohydrates that come with the food into alcohol.