Reishi, known scientifically as Ganoderma lucidum, is a type of mushroom that has been used in Traditional Chinese Medicine, or TCM, for over 4,000 years to treat asthma, fatigue and liver problems. It's currently used for stimulating the immune system in patients with HIV or cancer, and has been studied for other possible health conditions like diabetes and viruses. As with all herbs and medications, ganoderma has potential side effects that vary from mild to life-threatening.
There have been several reports of systemic allergic reactions from people taking ganoderma extract. One study conducted by the Centre for Biochemical Technology in India, found that out of 172 patients, 28.48 percent showed marked skin reactivity to ganoderma spores and 17.44 percent had a reaction to whole mushroom extracts.
Compounds found in reishi have the potential to inhibit the formation of platelets, vital for normal blood clotting in the arteries, and also may affect the clotting ability of thrombin in veins. The Natural Standard International Research Collaboration reports that a combination product containing ganoderma extract caused venous thrombosis in one out of eight patients being treated for prostate cancer. Due to these blood-thinning capabilities, if you're taking blood thinner medications such as Coumadin or Plavix, you should use caution when taking ganoderma.
Reishi mushrooms have the ability to lower blood pressure, according to a study at the Oral Roberts University School of Medicine Department of Pharmacology. This can lead to hypotension, and some patients have reported light-headedness and dizziness from using products with ganoderma. If you're taking any form of blood pressure medication, check with your doctor being using reishi or ganoderma extracts.
Children with Cancer
Ganoderma extract is frequently used by patients to help offset the effects of cancer and cancer treatments. However, in a study published in the "Canadian Journal of Clinical Pharmacology" in 2008, it was reported that three different extracts of ganoderma actually showed toxicity in cell cultures taken from children receiving chemotherapy. The researchers concluded that ganoderma extracts should be used with caution in patients, particularly children, undergoing chemotherapy.
The most frequently reported side effects from the use of ganoderma extract are stomach upset, diarrhea and constipation. In a reported case from Thailand, a patient developed chronic watery diarrhea from taking powdered lingzhi extract, the Asian name for ganoderma. The symptoms improved after the patient discontinued ingesting the mushroom. Also, due to the blood-thinning effects of the extract, some people may experience gastric bleeding.
Two patients, one in Hong Kong and the other in Thailand, had been taking boiled lingzhi without toxic effects. However, once they switched to taking the extract in concentrated powder form for one to two months, they developed liver hepatitis that led to their deaths. Although these are currently the only reported cases of hepatoxity of ganoderma, if you have liver disease, you should probably avoid taking any form of reishi.
Some patients have developed nasal/pharyngeal discomfort from taking ganoderma extracts. These symptoms were generally mild and included a dry nose, mouth and throat and nosebleed.