LISTERINE MOUTHWASH TEETH & GUM DEFENCE 250 ML Listerine Teeth and Gum Defence Mouthwash is quick and easy to use, a 30 second “sloosh” with Listerine after brushing and flossing reaches parts of the mouth that may be missed. Used twice daily, Listerine provides 24-hour protection against plaque.  Listerine products all contain the same combination of essential oils, which have been clinically proven to reduce plaque development by up to 56%.