Kills germs that cause bad breath, plaque & the gum disease Gingivitis. ADA Accepted (American Dental Association). Clinically proven. Kills germs by millions on contact. Listerine Antiseptic has been shown to help prevent and reduce supragingival plaque accumulation and gingivitis when used in a conscientiously applied program of oral hygiene and regular professional care. Its effect on peritonitis has not been determined. (Council on Scientific Affairs, American Dental Association.)