The reishi mushroom (known in China as Ling-Zhi or Ling-chih) is a fungus native to most temperate regions of eastern Asia. Wild reishi grows on decaying logs and the stumps of broad-leafed trees. Most reishi sold commercially is cultivated on wood chips. A slightly sweet, mild flavored mushroom, the reishi occurs in six different colors (black, red, green, white, yellow, and purple) which were traditionally used for different health purposes. The red variety is the one most commonly cultivated for commercial use.
Reishi contains several terpene compounds including ganoderic acids A, B, C, and D, lucidenic acid B and gandodermanontriol. It also contains ergosterol, coumarin, mannitol, polysaccharides, and resins. The terpene and polysaccharide fractions have demonstrated antioxidant effects.
Dosage recommendations for reishi vary with intended use. Common recommendations range from 1.5 to 9 grams per day. Reishi has very low toxicity and a very low occurrence of side effects. Minor reactions, such as loose stool, dry mouth, digestive disturbances, and skin rash have been reported in some individuals.