Peppermint oil is an excellent antiseptic and astringent. Peppermint is a cooling, relaxing herb that contains properties that help ease inflamed tissues, and inhibit bacteria and microorganisms. It also has pain-relieving and infection-preventing qualities. Due to its antiseptic properties, peppermint oil is commonly used in dental care products. Peppermint oil is a non-toxic mouth freshener, it removes bad breath and helps teeth and gums deal with germs.