Minty germ-fighting boldness! Cool Mint Listerine Mouthwash gives you 24-hour protection against plaque, bad breath and gum problems. A 30-second rinse with Cool Mint Listerine Mouthwash during your morning and night-time routines is all it takes to get 24-hour protection against germs that cause plaque and gum problems. Just 30 seconds of rinsing, twice a day.