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Turkey Tail, PSK and Cancer Care: What Is Known

PSK is a turkey tail extract approved as a cancer medicine in Japan, which is not the same as a turkey tail supplement. What trials in people with cancer found, and why your care team must know.

Content last updated . This page has not been medically reviewed.

Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.

What turkey tail is, and what PSK is

Turkey tail is the common name for Trametes versicolor, also written Coriolus versicolor. GBIF lists Trametes versicolor (L.) Lloyd as an accepted species in the family Polyporaceae. [3] The fungus has two different kinds of product, and the difference is the key to this page:
  • PSK (polysaccharide-K) is a purified extract. NCI describes it as "an approved mushroom product used for cancer treatment in Japan", used as an add-on to standard treatment, not on its own. [4] Some sources also call it krestin.
  • Turkey tail supplements (capsules, powders, extracts) are sold as dietary supplements. A cancer-center monograph says it is unclear whether PSK, PSP and other Coriolus extracts have comparable effects, and that many over-the-counter products are not standardized. [5] [6]

PSP (polysaccharopeptide) is a related extract made in China, from a different strain. [7] A result for PSK should not be applied to a turkey tail capsule of unknown content. See PSK, PSP and lentinan.

Traditional use

The cancer-center monograph says turkey tail ("yun zhi") is used in traditional Chinese medicine as a tonic. [8] That is traditional use only. The trials below are a separate matter.

What trials in people with cancer found

Cancer and questionWhat the source foundStrength of evidenceForm, population and amounts
Gastric (stomach), one 1994 Japanese trialFive-year survival 73.0% with PSK added vs 60.0% without. [9]Promising but limited (one trial from the 1990s)PSK added to chemotherapy after surgery; 262 patients
Gastric, pooled analysisA 2007 meta-analysis of 8,009 patients in eight trials found a survival hazard ratio of 0.88 (0.79 to 0.98). [10]Promising but limitedPSK plus chemotherapy vs chemotherapy alone
Gastric, Korean retrospective analysisNo difference between groups in five-year disease-free survival overall; a subgroup of earlier-stage patients did better with PSK. [11]Mixed310 patients (207 with PSK, 103 without); not randomized
ColorectalPooled odds ratio for five-year survival 0.71, favoring PSK (three trials, 1,094 patients). [12]Promising but limitedPSK added to standard treatment
Colorectal, Cochrane review (2022)"Low-certainty evidence of a small effect" on five-year survival; very low certainty on side effects of chemotherapy. [13] [14]Low certainty; the review notes the chemotherapy regimens do not reflect current practice [15]Seven randomized trials, 1,569 people, six of them in Japan, all using an extract [16]
LungA systematic review found 6 randomized trials, 5 non-randomized trials and 17 preclinical studies. [17]Mixed, with conflicting results on some outcomesPSK or other Coriolus extracts
BreastStudies measured immune markers, not survival or symptoms. [18]Insufficient evidence for clinical outcomesTurkey tail preparations in women after treatment

In the one phase 1 trial in women with breast cancer, nine women completed 6 weeks on 3, 6 or 9 grams a day of a turkey tail preparation; nine adverse events were reported (7 mild, 1 moderate, 1 severe) and immune markers showed trends, not proven benefit. [19] [20] That study was designed to test tolerability, not whether it helps.

What these trials do and do not show

  • Nearly all the survival data are for PSK in Japanese trials, alongside chemotherapy regimens of the time. They do not show that an over-the-counter turkey tail capsule gives the same result.
  • None of the sources we read says turkey tail cures or treats cancer on its own. In the Korean retrospective analysis NCI notes that the chemotherapy regimens differed between groups, introducing a potential bias. [21]
  • Laboratory and animal studies are separate from human trials and are not covered by the table. See human studies versus animal and laboratory research.
  • We did not read funding statements for these trials.

Official statements

  • NCI (U.S.), updated November 6, 2024: PSK is approved in Japan for cancer treatment; the FDA has not approved medicinal mushrooms for cancer. [4] [24]
  • Memorial Sloan Kettering monograph: Coriolus extracts are used in Japan and China after primary treatment, but the FDA has not approved them as additional cancer treatments. [25]

Frequently asked questions

Is turkey tail an approved cancer treatment?

PSK, an extract of turkey tail, is approved for cancer treatment in Japan. [4] In the United States the FDA has not approved medicinal mushrooms for cancer. [1]

Is a turkey tail supplement the same as PSK?

Not necessarily. Sources say many products are not standardized and that it is unclear if the extracts are comparable. [6] [5]

Can turkey tail be taken during chemotherapy?

We cannot say it is safe or unsafe. Few adverse events are reported with PSK, [22] but the sources do not address supplements with every chemotherapy. Ask the oncology team first.

Does turkey tail help people live longer?

For PSK added to standard treatment in Japanese trials, some analyses found better survival, [10] and the Cochrane review found low-certainty evidence of a small effect in colorectal cancer. [13] Evidence for supplements is not established.

What should I tell my care team?

Name the exact product, the form, and how long you have used it. Bring the label. See talking with a health professional.

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

Safety first: a supplement is not a cancer treatment
The U.S. National Cancer Institute (NCI) states that "The FDA has not approved the use of medicinal mushrooms as a treatment for cancer or any other medical condition". [1] The same summary says supplement ingredients may vary from lot to lot and that there is no guarantee labeled ingredients are present in the stated amounts. [2] Anyone having cancer treatment should tell the oncology team about every product they take, including mushroom capsules, powders and teas, before starting. Details are on mushroom supplements and cancer care. Do not delay or replace treatment with a mushroom product. Ask the prescriber or pharmacist before changing anything.
Safety and who should ask first
NCI says few adverse events have been reported with PSK. [22] Possible low-grade blood and stomach effects have been seen alongside chemotherapy, and may be caused by the chemotherapy itself. [23] Side effects, pregnancy and medicine questions are on turkey tail safety and side effects. Medicine interactions for supplements are explained at how interactions work.
References
  1. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  2. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  3. Global Biodiversity Information Facility (GBIF), species match for Trametes versicolor, usage key 2548311. GBIF species page. Read 2026-10-23 through the GBIF species-match service.
  4. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  5. Memorial Sloan Kettering Cancer Center, Coriolus versicolor (About Herbs). Read 2026-10-23.
  6. Memorial Sloan Kettering Cancer Center, Coriolus versicolor (About Herbs). Read 2026-10-23.
  7. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  8. Memorial Sloan Kettering Cancer Center, Coriolus versicolor (About Herbs). Read 2026-10-23.
  9. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  10. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  11. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  12. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  13. Coriolus (Trametes) versicolor mushroom to reduce adverse effects from chemotherapy or radiotherapy in people with colorectal cancer. Cochrane Database of Systematic Reviews, 2022. Read 2026-10-23.
  14. Coriolus (Trametes) versicolor mushroom to reduce adverse effects from chemotherapy or radiotherapy in people with colorectal cancer. Cochrane Database of Systematic Reviews, 2022. Read 2026-10-23.
  15. Coriolus (Trametes) versicolor mushroom to reduce adverse effects from chemotherapy or radiotherapy in people with colorectal cancer. Cochrane Database of Systematic Reviews, 2022. Read 2026-10-23.
  16. Coriolus (Trametes) versicolor mushroom to reduce adverse effects from chemotherapy or radiotherapy in people with colorectal cancer. Cochrane Database of Systematic Reviews, 2022. Read 2026-10-23.
  17. Fritz H, et al. Polysaccharide K and Coriolus versicolor extracts for lung cancer: a systematic review. Integrative Cancer Therapies, 2015. Read 2026-10-23.
  18. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  19. Torkelson CJ, et al. Phase 1 clinical trial of Trametes versicolor in women with breast cancer. ISRN Oncology, 2012. Read 2026-10-23.
  20. Torkelson CJ, et al. Phase 1 clinical trial of Trametes versicolor in women with breast cancer. ISRN Oncology, 2012. Read 2026-10-23.
  21. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  22. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  23. Memorial Sloan Kettering Cancer Center, Coriolus versicolor (About Herbs). Read 2026-10-23.
  24. National Cancer Institute (NCI), PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, Medicinal Mushrooms (PDQ), Health Professional Version, updated November 6, 2024. Read 2026-10-23.
  25. Memorial Sloan Kettering Cancer Center, Coriolus versicolor (About Herbs). Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.