Aromatherapy is the practice of using essential oils for therapeutic benefit. "Aromatherapy has been used for centuries," says Gujral. "When inhaled, the scent molecules in essential oils travel from the olfactory nerves directly to the brain and especially impact the amygdala, the emotional center of the brain."
Essential oils can also be absorbed by the skin. A massage therapist might add a drop or two of wintergreen to oil to help relax tight muscles during a rubdown. Or a skincare company may add lavender to bath salts to create a soothing soak.
Essential oils are basically plant extracts. They're made by steaming or pressing various parts of a plant (flowers, bark, leaves or fruit) to capture the compounds that produce fragrance. It can take several pounds of a plant to produce a single bottle of essential oil. In addition to creating scent, essential oils perform other functions in plants, too.