Extracts of turkey tail mushroom and its constituent PSK are used with conventional cancer treatment to improve survival and reduce risk of recurrence. The constituent PSP shows some benefit for pain, appetite, and percentage of body fat.

Safety and precautions

When used appropriately in daily recommended doses, both oral turkey tail mushroom and PSK and PSP extracts of turkey tail have appeared safe when used for extended periods. Studies of turkey tail in cancer commonly cite doses of 3 grams per day, though a phase 1 clinical trial in breast cancer cites safety with doses up to 9 grams per day for 6 weeks.1Torkelson CJ, Sweet E et al. Phase 1 clinical trial of Trametes versicolor in women with breast cancer. International Scholarly Research Notices Oncology. 2012;2012:251632.

Medical supervision is advised, preferably from a licensed clinician with experience in prescribing medicinal mushrooms.

Increased risk of cancer, recurrence, or mortality

The use of PSK with adjunct tegafur/uracil (UFT) has shown a slightly higher risk of recurrence and lower survival among people with colorectal cancer. 

  • Slightly worse disease-free survival and 3-year survival of unstated significance among people with stage 2B and stage 3 colorectal cancer treated with PSK and tegafur/uracil compared to tegafur/uracil plus leucovorin in a well designed mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects2Miyake Y, Nishimura J et al Multi-center Clinical Study Group of Osaka, Colorectal Cancer Treatment Group (MCSGO). Phase III trial comparing UFT + PSK to UFT + LV in stage IIB, III colorectal cancer (MCSGO-CCTG). Surgery Today. 2018 Jan;48(1):66-72.
  • A weak trendan apparent change due to a therapy, close to but not achieving full statistical significance (this is the CancerChoices definition; other researchers and studies may define this differently) toward higher risk of recurrence (lower disease-free survival) among people with stage 2 rectal cancer treated with adjunct tegafur/uracil (UFT) plus PSK compared to curative surgery in a mid-sized RCT of moderate quality3Okuno K, Aoyama T, Oba K, Yokoyama N, Matsuhashi N, Kunieda K, Nishimura Y, Akamatsu H, Kobatake T, Morita S, Yoshikawa T, Sakamoto J, Saji S. Randomized phase III trial comparing surgery alone to UFT + PSK for stage II rectal cancer (JFMC38 trial). Cancer Chemotherapy and Pharmacology. 2018 Jan;81(1):65-71.

Side effects or adverse events

A low rate of side effects, typically mild and temporary, has been reported in early clinical trials and in animal studies:4Eliza WL, Fai CK, Chung LP. Efficacy of Yun Zhi (Coriolus versicolor) on survival in cancer patients: systematic review and meta-analysis. Recent Patents on Inflammation & Allergy Drug Discovery. 2012 Jan;6(1):78-87; Shiu WCT, et al. A clinical study of PSP on peripheral blood counts during chemotherapy. Phytotherapy Research 1992;6:217-218; Jeitler M, Michalsen A, Frings D, Hübner M, Fischer M, Koppold-Liebscher DA, Murthy V, Kessler CS. Significance of medicinal mushrooms in integrative oncology: a narrative review. Frontiers in Pharmacology. 2020 Nov 11;11:580656; Kano T, Kumashiro R, Masuda H, Tamada R, Inokuchi K. Late results of postoperative long-term cancer chemotherapy for the gastric cancer patients subjected to curative resection. Japanese Journal of Surgery. 1983 Mar;13(2):112-6; Nakazato H, Koike A et al. Efficacy of immunochemotherapy as adjuvant treatment after curative resection of gastric cancer. Study Group of Immunochemotherapy with PSK for Gastric Cancer. Lancet 1994;343:1122-6.

  • Limited gastrointestinal upset, including nausea, vomiting, or diarrhea
  • Cough and temporary darkening of fingernails
  • Passing dark-colored stools (not due to blood in stools)
  • Low platelet count
  • Low white blood cell count (leukopenia)
  • Elevated liver enzymes

No evidence of increased major adverse events was found among people with cancer with use of turkey tail or its extracts as an adjunct to chemotherapy in a review of 13 RCTsrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects of low or moderate quality.5Eliza WL, Fai CK, Chung LP. Efficacy of Yun Zhi (Coriolus versicolor) on survival in cancer patients: systematic review and meta-analysis. Recent Patents on Inflammation & Allergy Drug Discovery. 2012 Jan;6(1):78-87.

Consult a healthcare professional immediately if you experience side effects.

Interactions with other therapies

Reduced liver function could impact the metabolism of other supplements, drugs and substances that are broken down by the liver, possibly increasing their side effects.

No undesirable herb-drug interactions were reported between turkey tail mushroom or its constituents and cytotoxic drugs in a systematic review.6Lam 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.

Do not use (contraindications)

Do not take turkey tail mushroom or its extracts if you have a known allergy/hypersensitivity to turkey tail, PSK, or any of its other components. There is insufficient evidence to establish safety of use during pregnancy and breastfeeding. Mushroom extracts are not recommended during pregnancy. 

Turkey tail mushroom should be used cautiously if you have known bleeding or clotting disorders or are using anticoagulant or antiplatelet agents, as it has been associated with low platelet counts (thrombocytopenia). Caution and medical supervision are also needed if you are using immunosuppressants.7Professional Resource: Coriolus Versicolor. Centre for Health Innovation. Viewed October 25, 2021. 

If you have any of these or other medical conditions, or if you are taking other drugs, herbs or supplements, before taking medicinal mushrooms consult a healthcare professional, preferably one with expertise in prescribing medicinal mushrooms such as a traditional Chinese medicine (TCM) practitioner, naturopathic oncologist or integrative medicine physician.

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Nancy Hepp, MS

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 Lead Researcher

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

Laura Pole, RN, MSN, 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, RN, MSN, OCNS Senior Clinical Consultant

Last update: February 10, 2024

Last full literature review: October 2021

CancerChoices provides information about integrative in cancer care, a patient-centered approach combining the best of conventional care, self care and evidence-informed complementary care in an integrated plan cancer care. We review complementaryin cancer care, complementary care involves the use of therapies intended to enhance or add to standard conventional treatments; examples include supplements, mind-body approaches such as yoga or psychosocial therapy, and acupuncture therapies and self-care lifestyle actions and behaviors that may impact cancer outcomes; examples include eating health-promoting foods, limiting alcohol, increasing physical activity, and managing stress practices to help patients and professionals explore and integrate the best combination of conventionalthe cancer care offered by conventionally trained physicians and most hospitals; examples are chemotherapy, surgery, and radiotherapy and complementary therapies and practices for each person.

Our staff have no financial conflicts of interest to declare. We receive no funds from any manufacturers or retailers gaining financial profit by promoting or discouraging therapies mentioned on this site.

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