Reishi Mushroom for Cancer

Reishi Mushroom for Cancer: Safety & Side Effects

This page covers safety information for Reishi Mushroom. See our complete Reishi Mushroom therapy guide →

Authors

Nancy Hepp, MS

past Lead Researcher

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Ms. Hepp is a researcher and communicator who has been writing and editing educational content on varied health topics for more than 20 years. She serves as lead researcher and writer for CancerChoices and also served as the first program manager. Her graduate work in research and cognitive psychology, her master’s degree in instructional design, and her certificate in web design have all guided her in writing and presenting information for a wide variety of audiences and uses. Nancy’s service as faculty development coordinator in the Department of Family Medicine at Wright State University also provided experience in medical research, plus insights into medical education and medical care from the professional’s perspective.

Nancy Hepp, MS past Lead Researcher

Maria Williams

Research and Communications Consultant

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Maria Williams is a research and communications consultant who brings over 15 years’ experience in research, consumer education, and science communication to CancerChoices. She has worked primarily in public health and environmental health.

Maria Williams Research and Communications Consultant

Laura Pole, MSN, RN, OCNS

Senior Clinical Consultant

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Laura Pole is senior clinical consultant for CancerChoices. Laura is an oncology clinical nurse specialist who has been providing integrative oncology clinical care, navigation, consultation, and education services for over 40 years. She is the co-creator and co-coordinator of the Integrative Oncology Navigation Training at Smith Center for Healing and the Arts in Washington, DC. Laura also manages the “Media Watch Cancer News That You Can Use” listserv for Smith Center/Commonweal. In her role as a palliative care educator and consultant, Laura has served as statewide Respecting Choices Faculty for the Virginia POST (Physician Orders for Scope of Treatment) Collaborative as well as provided statewide professional education on palliative and end-of-life care for the Virginia Association for Hospices and Palliative Care.

For CancerChoices, Laura curates content and research, networks with clinical and organizational partners, brings awareness and education of integrative oncology at professional and patient conferences and programs, and translates research into information relevant to the patient experience as well as clinical practice.

Laura sees her work with CancerChoices as a perfect alignment of all her passions, knowledge and skills in integrative oncology care. She is honored to serve you.

Laura Pole, MSN, RN, OCNS Senior Clinical Consultant

Reviewer

Andrew Jackson, ND

Research Associate

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Andrew Jackson, ND, serves as a CancerChoices research associate. As a naturopathic physician practicing in Kirkland, Washington, he teaches critical evaluation of the medical literture at Bastyr University in Kenmore, Washington. His great appreciation of scientific inquiry and the scientific process has led him to view research with a critical eye.

Andrew Jackson, ND Research Associate

Last update: March 16, 2026

Side effects and adverse reactions

Adverse effects noted in clinical trials include nausea, insomnia, mild discomfort (dizziness and dry mouth), diarrhea, stomach discomfort, and poor health.¹Jeitler M, Michalsen A et al. Significance of medicinal mushrooms in integrative oncology: a narrative review. Frontiers in Pharmacology. 2020 Nov 11;11:580656; Gelmon K, Kollmannsberger C et al. A phase I study of OMN54 (Aneustat™) in patients with advanced malignancies. Clinical Cancer Drugs. 2020;7(2):125-132; Gao Y, Zhou S, Chen G, Dai X, Ye J. A phase I/II study of a Ganoderma lucidum (Curt.: Fr.) P. Karst. Extract (Ganopoly) in patients with advanced cancer. International Journal of Medicinal Mushrooms. 2002;4(3):8. A few cases have described liver toxicity when the powdered form of reishi was used.²Wanmuang H, Leopairut J, Kositchaiwat C, Wananukul W, Bunyaratvej S. Fatal fulminant hepatitis associated with Ganoderma lucidum (Lingzhi) mushroom powder. Journal of the Medical Association of Thailand. 2007 Jan;90(1):179-81. One study found worse physical well-being among people with breast cancer treated with reishi, with increasing adverse effects at higher doses.³Bao PP, Lu W et al. Ginseng and Ganoderma lucidum use after breast cancer diagnosis and quality of life: a report from the Shanghai Breast Cancer Survival Study. PLoS One. 2012;7(6):e39343; Wanachiwanawin D, Piankijagum A et al. Ganoderma lucidum: a cause of pseudoparasitosis. Southeast Asian Journal of Tropical Medicine and Public Health. 2006 Nov;37(6):1099-102. Several individual cases of an elevated tumor marker have been detected among people using reishi.⁴Liang Y, He M et al. An abnormal elevation of serum CA72-4 by ganoderma lucidum spore powder. Annals of Clinical and Laboratory Science. Summer 2013;43(3):337-40; Yan B, Meng X et al. Ganoderma lucidum spore induced CA72-4 elevation in gastrointestinal cancer: a five-case report. Integrative Cancer Therapies. 2014 Mar;13(2):161-6.

Contraindications

Do not use reishi mushroom or its extracts if you have a known allergy or hypersensitivity to it or any of its components.

Drug interactions 

There are known drug interactions with this therapy.⁵Lam CS, Cheng LP, Zhou LM, Cheung YT, Zuo Z. Herb-drug interactions between the medicinal mushrooms Lingzhi and Yunzhi and cytotoxic anticancer drugs: a systematic review. Chinese Medicine. 2020 Jul 25;15:75. Interactions with medications and other interventions are complex. Always consult with a healthcare professional before adding any new therapy to your regimen. To learn more about interactions visit one of the trusted resources below: 

• EfficaSafe ›
• About Herbs ›

Interaction with cancer drugs

Some researchers have expressed concern reishi may possibly interfere with certain chemotherapy drugs that depend on oxidation to kill cancer cells due to its antioxidant activity, but there is no clinical evidence to support this.⁶Memorial Sloan Kettering Cancer Center. About Herbs: Reishi Mushroom. February 5, 2021. Viewed February 11, 2021; Brooks SL, Rowan G, Michael M. Potential issues with complementary medicines commonly used in the cancer population: A retrospective review of a tertiary cancer center’s experience. Asia Pacific Journal of Clinical Oncology. 2018 Oct;14(5):e535-e542. Always consult with your provider before beginning a new therapy. 

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