An<unk>  is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants.<unk> s are also known as volatile oils, ethereal oils, aetheroleum, or simply as the oil of the plant from which they were extracted, such as oil of clove. An<unk>  is<unk>  in the sense that it contains the essence of the plant's fragrance—the characteristic fragrance of the plant from which it is derived. The term<unk> " used here does not mean indispensable or usable by the human body, as with the terms<unk>  amino acid or<unk>  fatty acid, which are so called because they are nutritionally required by a living organism.<unk> s are generally extracted by distillation, often by using steam. Other processes include expression, solvent extraction, sfumatura, absolute oil extraction, resin tapping, wax embedding, and cold pressing. They are used in perfumes, cosmetics, soaps, air fresheners and other products, for flavoring food and drink, and for adding scents to incense and household cleaning products.<unk> s are often used for aromatherapy, a form of alternative medicine in which healing effects are ascribed to aromatic compounds. Aromatherapy may be useful to induce relaxation, but there is not sufficient evidence that<unk> s can effectively treat any condition. Improper use of<unk> s may cause harm including allergic reactions, inflammation and skin irritation. Children may be particularly susceptible to the toxic effects of improper use.<unk> s can be poisonous if ingested or absorbed through the skin.
Essential oil
Petroleum jelly
Emu oil
Gutter oil
Lavender oil
Tea tree oil
Coal tar
Balsam of Peru