Aromatherapy is actually a form of herbal medicine. However, instead of using the entire herb, it employs the fragrant "essential oil" that is released when a fresh herb is compressed or subjected to chemical extraction. Essential oils are also often used as fragrances in cosmetics and bath products.

When employed medicinally, essential oils are often evaporated into the air through the use of a humidifier. The famous Vicks VapoRub is a gel form of the essential oils of peppermint, eucalyptus, and camphor. Certain essential oils may also be applied directly to the skin or clothes so they will release their odor near the patient. Some essential oils are designed to be taken by mouth, but this is an uncommon usage.

Inhaled aromatherapy has become a popular, gentle treatment to reduce mild anxiety. It has also been tried for a variety of other conditions, including respiratory problems, postsurgical nausea, menstrual pain, and tension headaches.

Topical treatment with essential oils has shown possible value for fungal infections and hair loss. Essential oils specifically desigend for oral use have shown some promise for various digestive and respiratory problems.