Essential oils, also known as volatile oils, ethereal oils, or aetherolea is a concentrated hydrophobic liquid containing the oil of the plant from which they were extracted. The oil is considered essential in the sense that it has a distinct scent or essence from the plant. Essential oils are usually extracted by distillation, but could also be expressed from a solvent extraction.
Essential oils are used in perfumes, cosmetics, soaps and other products. They can also be used for flavoring food and drink, adding scents to incense or household cleaning products. Essential oils can be used for many different purposes.
Essential oils have also been used medicinally throughout history. They are often used as skin treatments. Sometimes they are used to treat more serious illness as well.
Over time, the use of essential oils declined in evidence-based medicine. Older textbooks still contain references and information regarding the use of essential oils.
In recent decades, interest in essential oils has revived. Aromatherapy, a branch of alternative medicine, uses essential oils and other compounds for curative purposes. Essential oils are also diluted in a carrier oil and used in massage. Essential oils can also be diffused into the air using a nebulizer, heated over a candle or burned as incense.