Concentrated in the root of the Ginseng plant are chemicals called ginsenosides, which can boost the immune system, stimulate the central nervous system and protect against the affects of stress. It is thought that the herb balances the stress hormones released from the pituitary and adrenal glands. It also has antioxidant properties and is said to reduce fatigue, improve digestion, increase mental stamina and lower blood cholesterol. Ancient Chinese healers used Ginseng as an aphrodisiac and clinical tests have shown it may well increase testosterone levels and sperm production.