Laurie her Page FAQ about aromatherapy.
Essential oils come from plants.
They are the volatile parts that give some plants or plantparts the strong smell. They are used by the plant to repel and fight insects and bacteria and may have many more uses for the plant that we are not yet aware of. They could be called the plants hormones, or the essence. Not all plants contain essential oil and not all of the parts of the plant do. Other methods using chemical solvents leave residues we do not want in our bodies.