Copper tanks in a brew house could be compared to a woman's stomach after she beat a drink-driving charge with evidence that her body actually brewed beer.

Drunken-driving charges against a woman in the US have been dismissed based on an unusual defence: Her body is a brewery.

A lawyer representing the woman in the New York area says her blood-alcohol level has been recorded at four times the legal limit when she hasn't had a drink.

She didn't discover her rare condition until after her arrest.

Attorney Joseph Marusak says he submitted medical evidence of his client's condition, known as "auto-brewery syndrome," to a suburban Buffalo judge who dismissed the driving while intoxicated charges in December.

The condition is believed to be caused by high levels of yeast in the gut. The woman is now on a low-carbohydrate diet that has brought it under control.

Marusak declined to name the woman, citing medical confidentiality laws.