Aromatherapy, or essential oils therapy, is using a plant's aroma-producing oils (essential oils) to treat disease. Essential oils are taken from a plant's flowers, leaves, stalks, bark, rind, or roots. The oils are mixed with another substance (such as oil, alcohol, or lotion) and then put on the skin, sprayed in the air, or inhaled. Oils can be massaged into the skin or pour them into bath water.