Aromatherapy oil. Bottle of peppermint aromatherapy oil and leaves of the peppermint plant, Mentha piperita. In aromatherapy, fragrant herb extracts, known as essential oils, are suspended in another oil called a carrier. This mix is then massaged into the skin, inhaled or added to bathing water. They may also be used to make creams, lotions or perfumes. Peppermint contains menthol, menthone, methyl acetate, tannic acid, terpenes and volatile oils; it is considered to be good for digestive problems. Aromatherapists claim that they can treat a range of disorders, but the technique is mainly used to create a sense of general well-being.