Essential oils are highly aromatic compounds extracted from a variety of botanical materials, including tree bark, flowers, stems, leaves, needles, plant roots, fruits and grasses. They are used in the production of perfumes, cosmetics, drinks, food flavoring, air fresheners, household cleaning products and aromatherapy oils. Essential oils also have a long history of use in traditional medicines. In health remedies, they find use as treatment oils, pastes and salves for minor aches, pains, congestion and coughing. In therapeutic applications, they are used to treat anxiety, insomnia and relaxation.
The tastes and aromas of natural essential oils are familiar to us. Oil of Wintergreen, an extract from the wintergreen group of plants which contains 98% methyl salicylate, is a familiar fragrance and flavor associated with toothpaste and chewing gum. While we may relate a particular aroma with a single compound, extracted oils are mixtures of varying concentrations of many compounds. In addition, essential oils are not oils in the conventional sense, that is, they are not long-chain hydrocarbon compounds, and their strong aromas do not always arise from the presence of an aromatic (phenyl) group in the oil's chemical composition. Instead, essential oils are complex mixtures of low viscosity fluids containing a surprising variety of molecular species and functional group chemistry.