Concerning this item Brushing only cleans 25% of your mouth; bacteria that are not removed could lead to gum and plaque issues. Listerine kills 99.9% of bacteria in your mouth, reaching every area. Plaque biofilm bacteria are eliminated by a special formula that deeply penetrates and contains four essential oils. In two weeks, Listerine helps lessen gum disease. Rinse twice a day for 30 seconds with undiluted 20ml for optimal results. After rinsing your mouth with water, wait 30 minutes before eating or drinking anything.