Ganoderma lucidum is a type of shelf fungus that usually grows on decaying hardwood and is valued by alternative medicine practitioners in Korea, China and Japan. It has the alternative names of reishi and ling zhi, and its proponents credit it with many beneficial effects.
Ganoderma lucidum is a member of the group of fungi known as polypores, which have many small holes on their lower surfaces, rather than the more common gills, for releasing spores. Mature fruiting bodies have glossy, deep red surfaces, while younger fungi have more yellow in their coloration. A variation restricted to the southeastern United States has a more yellow coloration even in maturity. Some scientists believe that the latter variety is actually a separate species. Both varieties tend to grow more readily in warm climates.
Ganoderma lucidum is now commonly cultivated for sale in the alternative medicine market. Early studies indicate that the fungus has a beneficial effect on the immune system and may be helpful in fighting the herpes virus. These studies also indicate that the fungus may help lower cholesterol levels. However, the studies that indicated these effects were on cultured cells and rodents, so they may not be applicable to humans.