The role of essential oils are bactericidal, deodorant, sedative, insect repellent, appetizer, promote digestion. The use of essential oils are, olfactory absorption method, massage absorption method, press method, bath method, and so on. Essential oils refer to the volatile aromatic substances obtained from the processing and extraction of spice plants or urinary animals.

Usually, essential oils are extracted from the flowers, leaves, roots, seeds, fruits, bark, resins, wood and other parts of the plant through steam distillation, cold pressing, liposuction, or solvent extraction to refine the extraction of volatile aromatic substances.

Essential oils are divided into diluted and undiluted, the volatility of essential oils is very strong, once in contact with the air will quickly evaporate, so essential oils must be stored in a dark bottle that can be sealed.

Not all plants can produce essential oils, only plants that contain balsam glands can produce essential oils, the distribution of balsam glands varies from plant to plant, from petals, leaves, rhizomes or tree trunks.