For about 2,000 years, the roots of P. ginseng have held an honoured place in Chinese medicine. Revered for its strength-giving and rejuvenating powers, the drug was used in the treatment of anaemia, diabetes, insomnia, neurasthenia, gastritis and sexual impotence. North American Indians used ginseng in many of their herbal formulas. The widespread use of ginseng is accompanied by the availability of abundant literature on the product and its purported activity. Reportedly acting favourably on the metabolism, its CNS-stimulating, CNS-sedative, tranquillizing, anti-fatigue, hypotensive and hypertensive activities have all been demonstrated. Classified as an adaptogen, it helps the body adapt to stress, improving stamina and concentration and providing a normalizing and restorative effect. It is not advisable to take ginseng continuously for three months, as long-term use can lead to symptoms similar to those of corticosteroid poisoning, including hypertension, nervousness and sleeplessness in some people, yet hypotensive and tranquillizing effects in others. Medicinal properties appear to reside in the saponins, ginsenosides and panaxosides.