Turkey Tail Mushroom

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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