Reishi mushroom (Ganoderma lucidum) is a fungus that is used in the traditional medical systems of China, Japan, Korea and other Asian countries. Reishi supplements come as capsules, tablets, extracts, powders, and teas.
(See also Overview of Dietary Supplements.)
Claims
Reishi mushrooms are said to treat elevated cholesterol levels or other hyperlipidemia. They are also said to boost the immune system, increase strength and stamina, treat cancer, and treat lower urinary tract symptoms in men.
Evidence
A 2016 Cochrane systematic review of use of reishi for treatment of cancer included 5 randomized, controlled-trials (373 subjects). The analysis found that patients who were given reishi in combination with their chemotherapy/radiation therapy had greater tumor regression with treatment than those treated with chemotherapy/radiation therapy alone, and quality of life improved. Treatment with reishi alone did not show a benefit. There was no evidence of survival benefit (1).
Adverse Effects
Nausea, insomnia, liver toxicity, anorexia, and chronic diarrhea have been reported.
Drug Interactions
Reishi may increase the risk of bleeding in patients treated with antiplatelet and anticoagulation drugs. It may also produce hypotension with antihypertensives and additive hypoglycemia with antihyperglycemic medications.
Reference
1. Jin X, Ruiz Beguerie J, Sze DM, Chan GC: Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database Syst Rev 4(4):CD007731, 2016. Published 2016 Apr 5. doi:10.1002/14651858.CD007731.pub3
