When a New York woman registered a blood alcohol level of .40 on a breath test after being pulled over for suspected DUI in 2015, police immediately rushed her to a hospital. But she had not had a drink in hours, and she had no symptoms despite having a life-threatening level of alcohol in her system. It turned out that the woman suffers from a rare medical condition called auto-brewery syndrome, which causes carbohydrates to turn into alcohol in the body. DUI charges that had been filed against the woman were dropped, and she underwent treatment for her condition.
Auto-brewery syndrome, also called gut-fermentation syndrome, is more common in Japan than anywhere else, but it is very rare there as well. Medical experts do not entirely understand the condition, which can be treated, but not cured.
A blood level alcohol content of .08 is the legal limit for driving in all 50 states, and levels approaching .30 are extremely dangerous and can be fatal. Yet people who suffer from auto-brewery syndrome can function at levels as high .40 or possibly higher. Still, having that much alcohol in the body is dangerous. One published study involved a 61-year-old man who had drunken-like symptoms frequently for years and was eventually diagnosed with auto-brewery syndrome. The man said he had suffered from it for 20 years.
Treatment for the condition is a diet that is low in carbohydrates, sugars, yeast and alcohol, though this does not always yield positive results. An anti-fungal medication was prescribed to the New York woman along with a restricted diet.
Cases of auto-brewery syndrome could serve to illustrate the fact that a blood alcohol test result does not prove that someone is drunk. Sometimes breath or blood tests can simply be mistaken, but in cases of auto-brewery syndrome, high blood alcohol content is not proof that someone was actually consuming drinks. Medical documentation of auto-brewery syndrome could be used as evidence in a defense mounted with the assistance of an attorney against a drunk driving charge.