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Turkey tail mushroom and chemotherapy side effects: what the evidence says

Small or mixed human studies suggest turkey tail extracts may soften the drop in immune cells during cancer treatment, but the effect on how people actually feel is uncertain.

3/5 Limited

Some human evidence: small trials, trials on a related outcome, or population studies that disagree. How we score

PubMed lists 89 papers on turkey tail and treatment side effects, and most human ones overlap the cancer page. We read every trial and review among them, and kept 10.

Cochrane, which looked for exactly this in colorectal cancer, found very low certainty for every side effect. Neutropenia was less common with extract (risk ratio 0.41), but in only 3 small studies; withdrawing from treatment because of side effects did not differ (1.03).

Small trials do show that blood measures respond: T cells fell less during radiotherapy and white cells rose. Those are lab numbers, not symptoms. Where symptoms were measured, the lung cancer trial saw no improvement, and the quality-of-life gains come from a 15-person trial and from uncontrolled studies.

Do not add it to treatment without telling your oncology team. Human drug-interaction data are thin (see the safety notes), and many patients in the reports below were told different things by different clinics.

The evidence ladder higher rungs count for more
  1. Meta-analyses of trialspooled randomized trials1
  2. Human studiestrials and population studies9
  3. Case reportssingle people0
  4. Animal studiesmostly rodents18
  5. Lab studiescells, test tubes13

The studies in people, read one by one

ResultTypeWhat they didWhat they found
MixedSystematic review / meta-analysis, 2022
1,569 people		Cochrane systematic review of 7 randomized trials of Coriolus extract with chemotherapy or radiotherapy, colorectal cancer
Measured: Treatment withdrawal, neutropenia, nausea, diarrhea, fatigue		Very low certainty throughout. Neutropenia risk ratio 0.41 (0.24 to 0.71), 3 studies. Withdrawal for adverse events 1.03 (0.45 to 2.34). Nausea 0.73, diarrhea 0.77, fatigue 0.76, all with intervals crossing 1. PubMed 36445793
PositiveRandomized trial, 2006
27 people		Double-blind placebo-controlled trial: Yunzhi 3.6 g plus danshen 1.4 g daily for 16 weeks during radiotherapy, nasopharyngeal cancer, Hong Kong
Measured: T-lymphocyte counts		T lymphocytes fell less than on placebo (p < 0.05). A combination, so turkey tail cannot be isolated, and blood counts are not symptoms. PubMed 17034283
MixedRandomized trial, 2003
68 people		Double-blind placebo-controlled trial: polysaccharide peptide for 28 days after treatment for advanced lung cancer
Measured: Blood counts, antibodies, symptoms		Leukocytes, neutrophils, IgG and IgM improved (P<0.05); cancer symptoms did not. PubMed 12814145
PositiveRandomized trial, 2008
20 people		Randomized trial: S-1 alone or with PSK after surgery, stage III gastric cancer
Measured: T-cell death		T-cell apoptosis 24.1% vs 19.1% with PSK. PubMed 18708731
PositiveRandomized trial, 2010
30 people		Randomized trial: chemoradiotherapy before rectal cancer surgery, with or without 4 weeks of PSK
Measured: Immune cell counts		Natural killer and cytotoxic T-cell counts rose and an immune-suppressing protein fell with PSK. PubMed 20393026
No effectRandomized trial, 2024
186 people		Randomized phase 2 trial: tegafur/uracil plus leucovorin, with or without PSK, colorectal cancer
Measured: Adverse events		Any-grade adverse events 59.5% without PSK, 52.1% and 59.2% with it; grade 3 or worse 13.5%, 9.6% and 9.9%. PubMed 38307591
PositiveRandomized trial, 2017
15 people		Placebo-controlled randomized trial, advanced liver cancer unfit for standard therapy
Measured: Quality of life		Social and emotional functioning were higher, and appetite loss and pain lower, than on placebo while on treatment. 15 people. PubMed 28375640
PositiveClinical trial, 2012
9 people		Phase 1 dose-escalation trial: turkey tail 3, 6 or 9 g/day for 6 weeks after radiotherapy for breast cancer, Bastyr and University of Minnesota
Measured: Safety, immune measures		Well tolerated: 9 adverse events (7 mild, 1 moderate, 1 severe). Lymphocyte counts trended up at 6 and 9 g/day. No control group. PubMed 22701186
PositiveClinical trial, 2010
82 people		Self-controlled study, Yunzhi plus danshen capsules for 6 months, breast cancer. Immune results from a similar 82-patient study: PMID 16047556
Measured: Quality of life		Improved physical function and less fatigue, compared with the same patients before. No control group; a combination. PubMed 20694182
PositiveClinical trial, 2011
25 people		Uncontrolled study: FOLFOX4 plus PSK, metastatic colorectal cancer, compared with published data
Measured: Neuropathy, neutropenia		Grade 3 neutropenia 24%; no grade 3 sensory neurotoxicity. Compared only with figures from other studies. PubMed 21566440

Where the sources agree, and where they don’t

2 of 4 kinds of source point toward a benefit, 0 toward no effect or harm, 2 are mixed. Agreement between independent kinds of evidence matters more than the number of papers in any one of them.

Kind of sourcePoints toDetail
Cochrane reviewMixedvery low certainty for every side effect
Small double-blind trialsPositiveblood counts, not symptoms; one is a combination
Symptoms and quality of lifeMixedno symptom gain in lung trial; gains in a 15-person trial
Patient reportsPositivereports credit it for white cell counts; uncontrolled

Beyond Google: 13 findings about Turkey tail mushroom from trial registries, FDA reports and patent offices that a normal search rarely shows. See them

What people report

We read public first-person posts and counted every outcome, good or bad. 2 reports about this condition, read on 2026-10-31; 0 mention side effects.

  • 2Helped
  • 0No effect
  • 0Got worse
  • 0Mixed
  • 0Too early

Why these counts prove nothing on their own: people who post are not a random sample, most take other treatments at the same time, and nobody checks the diagnosis. We show them because they tell researchers what to test next.

Read all 2 reports
  • Helped Takes turkey tail for low white cells, which rose, and says it helps fatigue. Inspire (Read from the search result text; thread not opened.)
  • Helped Reports a cancer center put them on turkey tail; says it helps with cold sores. HealthUnlocked (Read from the search result text; thread not opened.)

Every other paper we found

PubMed returned 89 papers for this search on 2026-10-31. We read the human studies above ourselves. The rest are sorted by type automatically from PubMed's labels, which are sometimes wrong. We removed 10 papers that only share a word with this search (papers that matched on a word only, mostly Huaier).

Animal studies 18
  1. Immunomodulatory effects of herbal formula of astragalus polysaccharide (APS) and polysaccharopeptide (PSP) in mice with lung cancer. Int J Biol Macromol, 2018
  2. Polysaccharide peptide induces a tumor necrosis factor-α-dependent drop of body temperature in rats. J Therm Biol, 2014
  3. Protein-bound polysaccharide-K reduces the proportion of regulatory T cells in vitro and in vivo. Oncol Rep, 2014
  4. Acute and subchronic oral toxicity of Coriolus versicolor standardized water extract in Sprague-Dawley rats. J Ethnopharmacol, 2011
  5. Immunoregulatory and anti-tumor effects of polysaccharopeptide and Astragalus polysaccharides on tumor-bearing mice. Immunopharmacol Immunotoxicol, 2008
  6. Modulation of antipyrine clearance by polysaccharide peptide (PSP) isolated from Coriolus versicolor in the rat. Food Chem Toxicol, 2006
  7. [Activation of antitumor immunity by intratumor injection of biological preparations]. Gan To Kagaku Ryoho, 2003
  8. Evaluation of polysaccharopeptide effects against C6 glioma in combination with radiation. Oncology, 2001
  9. Oral administration of PSK can improve the impaired anti-tumor CD4+ T-cell response in gut-associated lymphoid tissue (GALT) of specific-pathogen-free mice. Int J Cancer, 1997
  10. Polysaccharide peptide (PSP) restores immunosuppression induced by cyclophosphamide in rats. Am J Chin Med, 1997
  11. [Antitumor effect of PSK and its combined effect with CDDP on ovarian serous adenocarcinoma-bearing nude mice]. Nihon Sanka Fujinka Gakkai Zasshi, 1993
  12. Effects of biological response modifiers with different modes of action used separately and together on immune responses in mice with syngeneic tumours. J Int Med Res, 1992
  13. Involution of the thymus in tumor-bearing mice and its restoration by PSK. II. Mechanism of the involution and its restoration. J Clin Lab Immunol, 1987
  14. Effect of PSK on the serum level of immunosuppressive substance in splenectomized rats. In Vivo, 1987
  15. [Involution of the thymus in tumor-bearing mice and its restoration by PSK (2)]. Gan To Kagaku Ryoho, 1986
  16. Combined therapeutic effects of an immunomodulator, PSK, and chemotherapy with carboquone on rat bladder carcinoma. Cancer Chemother Pharmacol, 1985
  17. Effect of a protein-bound polysaccharide preparation, PS-K, on dimethyl hydrazine induction of intestinal tumors in rats. Gan, 1983
  18. [Coenzyme Q10 in cancer chemotherapy--experimental studies on augmentation of the effects of masked compounds, especially in the combined chemotherapy with immunopotentiators]. Gan To Kagaku Ryoho, 1983
Lab studies 13
  1. Strike Mitochondria By Enzyme-Instructed Self-Assembled Peptides for Effective Immunogenic Anti-Tumor Therapy. Int J Nanomedicine, 2025
  2. Enhanced Anti-Cancer Potential: Investigating the Combined Effects with Coriolus versicolor Extract and Phosphatidylinositol 3-Kinase Inhibitor (LY294002) In Vitro. Int J Mol Sci, 2025
  3. Therapeutic Effects of Medicinal Mushrooms on Gastric, Breast, and Colorectal Cancer: A Scoping Review. Cureus, 2023
  4. Musarin, a novel protein with tyrosine kinase inhibitory activity from Trametes versicolor, inhibits colorectal cancer stem cell growth. Biomed Pharmacother, 2021
  5. Can polysaccharide K improve therapeutic efficacy and safety in gastrointestinal cancer? a systematic review and network meta-analysis. Oncotarget, 2017
  6. [A retrospective study of UFT and oral leucovorin plus PSK combination adjuvant chemotherapy in patients with stage III colon cancer]. Gan To Kagaku Ryoho, 2012
  7. [Effect of DC therapy combined with chemotherapy in advanced cancer cases]. Gan To Kagaku Ryoho, 2003
  8. Immunomodulating components from chinese medicines. Pharm Biol, 2000
  9. Changes in serum soluble IL-2 receptors (sIL-2R) and immunosuppressive acidic protein (IAP) associated with chemotherapy for lung cancer. Anticancer Res, 1997
  10. [Surgical stress and lymphocyte function. Effects of PSK to prevent cellular immunosuppression]. Nihon Ika Daigaku Zasshi, 1993
  11. [Evaluation of radiation immunochemotherapy in the treatment of malignant glioma. Combined use of ACNU, VCR and PS-K]. Hokkaido Igaku Zasshi, 1983
  12. Late results of postoperative long-term cancer chemotherapy for the gastric cancer patients subjected to curative resection. Jpn J Surg, 1983
  13. [Malignant melanoma in Japan: unique distribution and effect of DAV chemoimmunotherapy]. Gan To Kagaku Ryoho, 1982
Reviews 12
  1. Critical Review on the Anti-Tumor Activity of Bioactive Compounds from Edible and Medicinal Mushrooms over the Last Five Years. Nutrients, 2025
  2. Mushrooms and Colorectal Cancer: Unveiling Mechanistic Insights and Therapeutic Innovations. Phytother Res, 2025
  3. Herb-drug interactions between the medicinal mushrooms Lingzhi and Yunzhi and cytotoxic anticancer drugs: a systematic review. Chin Med, 2020
  4. Anticancer potentiality and mode of action of low-carbohydrate proteins and peptides from mushrooms. Appl Microbiol Biotechnol, 2020
  5. Practical Application of "About Herbs" Website: Herbs and Dietary Supplement Use in Oncology Settings. Cancer J, 2019
  6. Coriolus versicolor polysaccharopeptide as an immunotherapeutic in China. Prog Mol Biol Transl Sci, 2019
  7. Preclinical and clinical studies of Coriolus versicolor polysaccharopeptide as an immunotherapeutic in China. Discov Med, 2017
  8. [Immunomodulatory and antitumor properties of polysaccharide peptide (PSP)]. Postepy Hig Med Dosw (Online), 2015
  9. Biological mechanism and clinical effect of protein-bound polysaccharide K (KRESTIN(®)): review of development and future perspectives. Surg Today, 2012
  10. [Current status and future perspectives on chemotherapy in patients with gastric cancer: can the clinical data from Japan lead to a standard international therapy?]. Nihon Geka Gakkai Zasshi, 2001
  11. The use of mushroom glucans and proteoglycans in cancer treatment. Altern Med Rev, 2000
  12. [Recent advance and its problem of postoperative immunotherapy on gastric cancer--with references to effects and host dependent factors]. Nihon Geka Gakkai Zasshi, 1991
Other papers, not yet read by us 29
  1. Hemangiosarcoma in a Dog: Unusual Presentation and Increased Survival Using a Complementary/Holistic Approach Combined with Metronomic Chemotherapy. Case Rep Vet Med, 2018
  2. Phase III trial comparing UFT + PSK to UFT + LV in stage IIB, III colorectal cancer (MCSGO-CCTG). Surg Today, 2018
  3. Polysaccharide K and Coriolus versicolor extracts for lung cancer: a systematic review. Integr Cancer Ther, 2015
  4. [A case of gastric cancer with peritoneal metastasis successfully treated with multidisciplinary therapy]. Gan To Kagaku Ryoho, 2013
  5. 5-Fluorouracil, mitomycin-c, and polysaccharide-k versus uracil-ftorafur and polysaccharide-K as adjuvant chemoimmunotherapy for patients with locally advanced gastric cancer with curative resection. Onkologie, 2013
  6. Immunotherapy eradicates metastases with reversible defects in MHC class I expression. Cancer Immunol Immunother, 2011
  7. Comparison between intravenous and oral postoperative adjuvant immunochemotherapy in patients with stage III colorectal cancer. Oncol Rep, 2008
  8. Comparison between intravenous and oral postoperative adjuvant immunochemotherapy in patients with stage II colorectal cancer. Oncol Rep, 2008
  9. [A case of long-term survival of 5 years after operation and chemotherapy for type 4 gastric cancer with peritoneal dissemination]. Gan To Kagaku Ryoho, 2008
  10. A randomized phase III trial of postoperative adjuvant therapy with S-1 alone versus S-1 plus PSK for stage II/IIIA gastric cancer: Hokuriku-Kinki Immunochemo-Therapy Study Group-Gastric Cancer (HKIT-GC). Jpn J Clin Oncol, 2006
  11. [A patient with hepatic, pulmonary, and nodal metastases of colon cancer responding to CPT-11/TS-1 therapy]. Gan To Kagaku Ryoho, 2006
  12. Immunomodulatory activities of Yunzhi and Danshen in post-treatment breast cancer patients. Am J Chin Med, 2005
  13. [A case of metastatic submandibular lymphnode treated successfully with palliative oral (5-FU + PSK) chemotherapy in the elderly]. Gan To Kagaku Ryoho, 2005
  14. [Weekly administration of paclitaxel might be beneficial against TS-1-resistant recurrent gastric cancer--a case report]. Gan To Kagaku Ryoho, 2004
  15. Adjuvant immunochemotherapy with oral Tegafur/Uracil plus PSK in patients with stage II or III colorectal cancer: a randomised controlled study. Br J Cancer, 2004
  16. Adjuvant therapy with protein-bound polysaccharide K and tegafur uracil in patients with stage II or III colorectal cancer: randomized, controlled trial. Dis Colon Rectum, 2003
  17. [Chemotherapy by combination of low-dose CPT-11 and PSK in an elderly man with liver metastasis from gastric cancer]. Gan To Kagaku Ryoho, 2001
  18. Gastric cancer in Asia: progress and controversies in surgical management. Aust N Z J Surg, 1998
  19. Immunochemotherapies versus chemotherapy as adjuvant treatment after curative resection of operable breast cancer. Anticancer Res, 1995
  20. Efficacy of immunochemotherapy as adjuvant treatment after curative resection of gastric cancer. Study Group of Immunochemotherapy with PSK for Gastric Cancer. Lancet, 1994
  21. [A case of secondary leukemia induced by chemotherapy with a CDDP-based regimen for gastric cancer 5 years following radical resection]. Gan To Kagaku Ryoho, 1993
  22. Postoperative adjuvant immunochemotherapy with mitomycin C, tegafur, PSK and/or OK-432 for gastric cancer, with special reference to the change in stimulation index after gastrectomy. Jpn J Surg, 1990
  23. [Metastatic liver cancer from the stomach successfully treated by combined immunochemotherapy and transarterial embolization]. Gan To Kagaku Ryoho, 1989
  24. [AUFRAP therapy: combined modality treatment of malignant gliomas with intraarterial infusion of ACNU]. Gan To Kagaku Ryoho, 1988
  25. [Two cases of unresectable pancreatic cancer responding to combined chemotherapy with cisplatin, PSK and UFT]. Gan To Kagaku Ryoho, 1987
  26. [A case of malignant lymphoma in the skull after head injury associated with multiple bone tumors]. No Shinkei Geka, 1985
  27. [Enhancement of irradiation effect in carcinoma of the uterine cervix with the administration of protein-bound polysaccharide kureha (PS-K)]. Nihon Sanka Fujinka Gakkai Zasshi, 1985
  28. [A multi-institutional study on postoperative adjuvant immunochemotherapy of gastric cancer]. Gan To Kagaku Ryoho, 1985
  29. Krestin (PSK). Cancer Treat Rev, 1984

Other conditions Turkey tail mushroom has been studied for

Checked against PubMed on 2026-10-31. Everything we know about Turkey tail mushroom