The essential oil is a concentrated hydrophobic liquid containing volatile aromatic compounds from plants. Essential oils are also known as volatile oils or simply as vegetable oils of the plant from which they are extracted, such as clove oil. They carry the distinctive aroma of the plant.
Essential oils are usually extracted by distillation, often with the help of steam. Another process involves solvent extraction.

It is believed that the earliest techniques and methods used to produce essential oils are Ibn al-Bajar (1188-1248), an Andalusian doctor, pharmacist and chemist
Because of their saturation and dense aroma, essential oils are not used in pure form but diluted. Essential oils are used in perfumery, cosmetics, soap making, aromatics for food and beverages, and for adding fragrances to products such as incense and household cleaners. A wide range of applications is found in aromatherapy and prevention of various diseases.

Essential oils have been used as a medicine in the past