Essential oils are extracted from plants and flowers and are a concentration of plant essence. The art of using essential oils is called aromatherapy and includes making items for skin care, massage, and specific ailments such as insomnia, nausea, pain, or stress relief. You are practicing aromatherapy whenever you cook in the kitchen. The smell of freshly baked bread brings a sense of comfort and peace; the aroma of warm chocolate chip cookies invites your mouth to water and your expectations to rise; and simmering cinnamon and allspice in a little water on the stove at Christmas adds to the holiday ambiance. To get started, we offer a link to a great aromatherapy book that tells you how to do it all. One note of CAUTION. There is a very real difference between essential oils and fragrance or fragrance oils. Only essential oils are plants extracts; the rest are chemicals.
The Illustrated Encyclopedia of Essential Oils: The Complete Guide to the Use of Oils in Aromatherapy & Herbalism