Reishi mushrooms (Ganoderma lucidum) grow on the trunks or stumps of trees. They originate in China and Japan and are cultivated in British Columbia, Canada, where they are also known as Ganoderma. In China, the fungus was known as "the mushroom of immortality," and in Japan as Reishi or Mannentake, "ten thousand year old mushroom," both indicative of the expectations of their devotees.
The active compounds in reishi mushrooms appear to be a group of ganoderic acids or triterpenes, ergosterols and polysaccharides. But their proteins contain all essential amino acids, and most common non-essential amino acids and amides. Their fatty acids are mostly unsaturated, and they are rich in vitamins B3, B5, C and D and minerals such as calcium, phosphorus and iron. In addition, reishi mushrooms are the only known source of the triterpenoids known as ganoderic acids, with a molecular structure similar to steroid hormones, while they also possess the most active polysaccharides among all medicinal plant sources.
Reishi mushrooms show anti-tumor activity linked to their polysaccharides and fatty compounds, which are probably ergosterols. They can neutralize free radicals such as carbon tetrachloride and ethionine in animal livers, and can reverse fatty depositions. They can increase immunoglobulin A in chronic bronchitis patients, and they are used to offset the side effects of cancer treatment including chemotherapy, radiation and surgery, high altitude stress, high cholesterol and triglycerides, high blood pressure, chronic fatigue syndrome, concentration difficulties, deregulation of immune responses, insomnia, poor digestion, weaknesses of the lungs, wasting syndrome, etc.
Reishi mushrooms are in the most highly rated category of herbs in terms of multiple benefits and absence of side effects ("Superior") in traditional Chinese medicine. They seem to be extremely adaptable in their benefits. Thus while increasing some immune responses for cancer patients, they also inhibit auto-immune disorder responses as in myasthenia gravis. Again, they reduce the histamine released in allergic reactions, but also help prevent anaphylactic shock. In other words, they seem to provide an adaptable support for some body systems, regulating their response not according to a determined curative direction, but according to what is required in the specific case.
No toxicity, although high doses of powdered mushrooms may initially cause stomach upsets, dry mouth and skin rash.