Aromatherapy, commonly associated with complementary and alternative medicine (CAM), is the use of volatile liquid plant materials, known as essential oils (EOs), and other aromatic compounds from plants to affect someone's mood or health. The word was coined in the 1920s by French chemist Ren Maurice Gattefoss.

The main branches of aromatherapy include:

• Home aromatherapy (self treatment, perfume & cosmetic use)
• Clinical aromatherapy (as part of pharmacology and pharmacotherapy)
• Aromachology (the psychology of odors and their effects on the mind)