Listerine Stay white Mouthwash is specially formulated with zinc chloride which prevents tartar build up to fight staining. It kills more germs left behind after brushing and reduces plaque more than brushing alone. It kills germs above and below the gum line to keep gums healthy and maintain healthy gums. Listerine Stay white Mouthwash is specially formulated with zinc chloride which prevents tartar build up to fight staining.