Kava-kava, or simply kava, as it is also known, is the massive root stock or leaf of a highly variable sprawling shrub in the pepper family, found throughout the South Pacific islands from Hawaii to New Guinea. The plant has been cultivated for so many centuries that its exact origin is unclear. Like garlic, kava in its present form evolved during 3,000 years of cultivation.
Polynesians have used a thick brew of the fresh or dried root as their main beverage for centuries. A similar beverage, prepared from ground roots, is often imbibed in social or ceremonial settings. The cultural role of kava in Pacific societies has been compared to that of wine in southern Europe. A decoction of the rootstock has reportedly been used for the treatment of gonorrhea, chronic cystitis and other urinary infections, menstrual problems, migraine headache, insomnia, and other conditions.
The first herb products made from kava appeared in Europe in the 1860s. By the 1890s, kava extracts were available in German herb shops. The first pharmaceutical preparation, a tincture used as a mild sedative and to lower blood pressure, became available in Germany thirty years later.
In Germany the rootstock and its preparations are allowed to be labeled for conditions of nervous anxiety, stress, and unrest. In Europe, kava extracts are often combined with pumpkin seed, for its diuretic effect, in the treatment of irritable bladder syndrome.
Compounds called kavalactones give kava root its primary effects. Two of them, in specified dosages, have pain-relieving effects comparable to aspirin. One kavalactone produces a numbing effect in the mouth upon chewing the root or drinking kava preparations. Kavalactones have been shown to relax muscles by affecting muscular contractility rather than by blocking neurotransmitter signals in nerves.
Kava root tablets, capsules, tinctures, and dried root are available in the American market as are kava leaf products. Standardized European products contain 70 percent kavalactones.
The German health authorities warn that kava should not be used during pregnancy, lactation, or depression. Because of its apparent sedative action, it should not be taken with alcohol, or when operating machinery or vehicles. No side effects are associated with small amounts of kava preparations. In the copious amounts consumed on South Sea islands, side effects of longterm use include temporary yellow discoloration of the skin, hair, and nails; rare allergic skin reactions; and vision disturbances. Excessive use has also caused skin itching and sores. In some Western popular articles and books, kava has been described as a "hypnotic", but, contrary to the wishful thinking of some promoters, it is neither hallucinogenic, nor stupefying, nor does it produce any physical addiction.