Essential oil characteristics and effects, but also the products of the very same tree can vary grossly. Lavender oil has long been used in the production of perfume. However, it can be estrogenic and antiandrogenic, causing problems for prepubescent boys and pregnant women, in particular. Lavender essential oil is also used as an insect repellent. Rose oil is produced from the petals of "Rosa damascena" and "Rosa centifolia". Steam-distilled rose oil is known as "rose otto", while the solvent extracted product is known as "rose absolute". The potential danger of an essential oil is sometimes relative to its level or grade of
Essential oil are a mixture of essential oil, waxes, resins, and other lipophilic (oil-soluble) plant material. Although highly fragrant, concretes contain large quantities of non-fragrant waxes and resins. Often, another solvent, such as ethyl alcohol, is used to extract the fragrant oil from the concrete. The alcohol solution is chilled to for more than 48 hours which causes the waxes and lipids to precipitate out. The precipitates are then filtered out and the ethanol is removed from the remaining solution by evaporation, vacuum purge, or both, leaving behind the "absolute". Supercritical carbon dioxide is used as a solvent in supercritical fluid extraction.