Ginseng (Panax ginseng) is native to north-eastern China, eastern Russia and Korea.  The related species, Panax quinquefolious, occurs in the eastern United States and Canada. Ginseng has an ancient and rich history as a medicinal plant and has been praised for its remarkable therapeutic benefits for about 7,000 years.  Its value was so great that wars were fought for control of the forests in which it thrived.  An Arabian physician brought ginseng back to Europe in the 9th century, yet its ability to improve stamina and resistance to stress only became common knowledge in the West during the 18th century. Ginseng increases mental and physical efficiency and resistance to stress and disease.  It often shows a dual response like sedating or stimulating the central nervous system according to the condition it is being taken to treat.  In the West, ginseng is regarded as a life-enhancing tonic.