Hyssop is an evergreen perennial herb native to southern Europe and central Asia and cultivated in many other regions of the world. A member of the mint family, hyssop grows to approximately 60 centimeters in height, with an erect quadrangular stem, which is branched and shrubby. The leaves of the plant are smooth and lanceolate, dark green on top and paler underneath. Hyssop flowers from June to October, bearing whorls of small white, pink, or blue-violet blossoms at the tops of the branches and stems. The above-ground portions of the plant are used for culinary and health purposes.
Hyssop contains a volatile oil, the chief components of which include pinocamphone, alpha-pinene, and beta-pinene.
A typical daily dosage recommendation is one to two cups of a decoction made by combining 1 tsp of dried herb to each cup of water. The herb appears to be safe and free of side effects at this dosage range. Use of the isolated volatile oil (or long-term use of the herb) is not recommended because its high pinocamphone concentration has been known to cause toxic convulsions similar to epileptic seizures.