This essential oil is also considered an antispasmodic herb that helps relieve gastrointestinal pains; however, Peppermint oil can also be used topically to permeate the skin and work as an analgesic and anti-inflammatory. Peppermint oil contains around 25% to 50% menthol which makes it a soothing and cooling rub for sore muscles. Peppermint oil relaxes the muscles and works as a counterirritant (basically, a solution that works on the surface of the skin to counteract with pain that is underneath the skin).