Wild or cultivated shrub having erect, branched stems with a woody lower portion; opposite, whitish-green, narrow leaves; lilac-purple flowers in glomerulate spikes placed at the tip of branches. The plant grows in Mediterranean areas (French-Italian Alps), England, North America, North Africa, and several Euro pean countries. The parts used are the flowering tops and stalks. Lavender has a sweet, herbaceous, slightly floral odor. The essential oil is obtained by steam distillation of the freshly cut flowering tops and stalks. (A terpeneless oil also is prepared by carefully distilling the essential oil under vacuum.) It is a pale yellow to yellow-amber, mobile liquid with an ester-like, slightly camphoraceous odor. The yields in essential oil range between 0.6% to 1%. The physical-chemical constants vary, depending on the source. The main constituents of lavender include l-linalool, l-linayl acetate, probably furfural, valeric aldehyde, amyl alcohol, α-pinene, cineol, small amounts of d-borneol, geraniol, terpenes, and traces of coumarin. The English lavender oil is distilled from a different lavender variety, L. intermedia Loisel. It has a higher linalool but a lower linalyl ester content that seldom exceeds 10%; French lavender contains from 30 to 60% esters. Lavender essential oil does not withstand prolonged aging. Use of the product within 12 to 15 months from preparation is advisable. Several hybrid lavender varieties are used today for distillation. These oils are commer cially available under different trade names that define somewhat the characteristics of the oil. In France, the main types offered commercially are Matheronne and Maillette. The derivatives are infusion, tincture, concrete, and absolute. By extraction with benzene or other solvents of the partially dried flowering herb, the concrete is prepared in approximately 1.5 to 2.0% yields. The absolute is prepared from the concrete in approx imately 50 to 60% yields. The concrete is a more or less liquid, viscous mass with a dark-green color and sweet, herbaceous odor. The absolute is also dark-green and is, sometimes, decolorized using activated charcoal. The main constituents include linalool, linayl acetate, coumarin, an umbelliferone methyl ether, and cou maric acid.