Reishi Side Effects and Liver Injury Reports

Liver warning first. Memorial Sloan Kettering Cancer Center (MSK) lists liver injury among possible side effects of reishi, and describes case reports of liver toxicity with powdered reishi, leading to death in one instance. [1] A 2007 report in the Journal of the Medical Association of Thailand described fatal fulminant hepatitis after reishi mushroom powder. [2] A 2023 case report described acute hepatitis in a 47-year-old man who had headache and abdominal pain after consuming reishi powder and alcohol. [3] MedlinePlus explains that jaundice turns the skin and the whites of the eyes yellow and can have several causes, including liver diseases and medicines. [4] If you have taken a reishi product and develop belly pain, yellowing of the skin or eyes, or other new symptoms you cannot explain, contact a clinician promptly. For emergencies call 911. See liver safety and supplements.

Reishi and the liver: what the reports say

These are individual case reports, which cannot show how common a problem is or prove cause.

The liver reports we read involve powder forms and, in two cases, other medicines or alcohol, so the role of reishi itself is not certain. A dedicated NIH LiverTox page on reishi exists, but it could not be read in this session, so it is not used here.

Other reported effects

• MSK lists nausea and insomnia, and says dry mouth, constipation, itching and vertigo have been reported. [1]
• A Cochrane review of cancer trials noted one study with minimal side effects, including nausea and insomnia, and no significant blood or liver toxicity reported. [5]
• A Cochrane review in people with type 2 diabetes found people on reishi for four months were 1.67 times as likely to report an adverse event (95% CI 0.86 to 3.24, so not a clear difference); the review described them as not serious. [6]
• A 2025 meta-analysis of 17 trials found no significant effect on liver enzymes. [7]

What short trials show, and what they do not

In 16 healthy volunteers, no adverse effects were observed over 10 days of an extract, and the authors said a longer safety trial is warranted. [8] In an 84-day trial in healthy adults, kidney and liver function markers did not change significantly. [9] A systematic review of mushrooms in cancer care found most adverse effects were mild (grade 2 or lower) across many preparations. [10] Short trials in small groups can miss rare reactions such as liver injury. "Safe long term" has not been shown by the sources we read.

Other cases and groups

• Children: a 2026 case report described a 9-year-old with prematurity, cerebral palsy and well-controlled epilepsy who developed myoclonic seizures, hallucinations and altered mental status after several medicinal fungi supplements, including reishi and cordyceps, with resolution after stopping. [11] MSK describes a similar case in a 9-year-old. [1] See children and teens.
• Pregnancy and breastfeeding: not described in the sources we read. See pregnancy and breastfeeding.
• Allergy: Proper evidence not found for reishi-specific allergy. We searched PubMed for Ganoderma or reishi with allergy and asthma terms and found no usable report. See mushroom allergy.
• Cancer tests: MSK says spore powder may raise the tumor marker CA72-4, which can interfere with cancer test results. [1]
• Bleeding and surgery: see reishi and medicines.

Contamination and product questions

Products differ in species, part and extraction, and ingredients can vary from lot to lot, according to the NCI summary. [12] See quality testing and certifications.

Who should ask a clinician first

Anyone with liver disease or who drinks alcohol regularly, takes medicines cleared by the liver, is pregnant, has an immune or autoimmune condition, takes blood thinners, is having surgery, or is choosing a product for a child. Report any reaction using side effects and reporting.