Aromatherapy is a pseudoscience that purports to improve psychological and physical well-being by using aromatic materials such as essential oils and other aroma molecules. It is provided as a complementary therapy or as a kind of alternative medicine, with the first indicating that it is used in addition to standard treatments and the latter meaning that it is used instead of standard, evidence-based treatments. Aromatherapists, or persons who have expertise in the practice of aromatherapy, use blends of potentially therapeutic essential oils that can be applied topically, massaged, inhaled, or dissolved in water. These essential oil molecules are inhaled or absorbed through the skin during an aromatherapy massage. They are supposed to affect the limbic system, a brain region known to be engaged in emotion, and hence induce good changes in the mind and body.