Listerine contains methyl salicylate (the same as aspirin), thymol (an anti fungal), menthol and eucalyptus. It is great for toothache, mouth ulcers or a sore throat. At the other end, it can treat tinea and cracked heels. It can help with nits and itchy insect bites, or fleas on your pets. It’s also really handy around the house.