Turkey tail (Trametes versicolor, Coriolus versicolor)

Medicinal mushroom. In Japan PSK (Krestin) approved as chemotherapy adjuvant for gastric cancer since 1977. In EU and AEMPS not registered as medicine; sold as supplement

ATC code: A11JA-TURKEY-TAIL(Turkey tail (Trametes versicolor, PSK/PSP))

Brand names – supplements: Host Defense Turkey Tail, Real Mushrooms Turkey Tail, Now Turkey Tail, Krestin (Japan only)Supplements are not tested in clinical trials and are not registered as medications.

Updated 19 Jun 2026 · Methodology

Indications

Cancer prevention through supplements

Adjunct

Trametes versicolor (PSK, Krestin) is the only medicinal mushroom with relatively convincing evidence as chemotherapy adjuvant. Fritz 2015 (Integr Cancer Ther) systematic review of 5 RCTs in 1094 lung cancer patients: PSK added to standard chemotherapy improved 5-year survival by 9% vs chemotherapy alone. In Japan PSK has been approved since 1977 as adjuvant in gastric cancer after radical surgery. ESMO 2024 for gastric cancer lists FLOT or CapeOX/SOX first-line adjuvant, platinum doublets with trastuzumab (HER2+) or nivolumab (PD-L1+) in metastatic disease; PSK is not in European international guidelines and remains in Japanese practice. As monotherapy supplement does not replace standard treatment; used only in combination under oncology supervision. AEMPS does not register turkey tail as medicine.

Sources

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Chronic fatigue

Not recommended

Turkey tail is a medicinal mushroom (Trametes / Coriolus versicolor) and the source of the polysaccharides PSK and PSP. It gets promoted as an immune supplement and for chronic fatigue. No convincing benefit has been shown for chronic fatigue itself: there is no solid evidence base for this use. What actually helps with persistent fatigue is finding and treating the cause (for example anemia, thyroid problems, sleep disorders, or depression), and for chronic fatigue syndrome, working on sleep, activity pacing, and symptoms together with a clinician. Don't take this supplement in place of treatment with proven benefit, or you risk missing the care you need.

Sources

ICD-10: R53 · ICD-11: MG22

Immune support and respiratory infection care

Not recommended

Trametes versicolor is sold for «immunity boosting» via T and NK cell stimulation. In healthy people for cold and respiratory viral infection prevention no quality RCTs with frequency or symptom duration endpoints. AAFP and SEIMC for the common cold recommend symptomatic therapy; turkey tail is not in international guidelines.

Sources

Memorial Sloan Kettering Cancer Center: Coriolus Versicolor (Turkey Tail) monograph (2023)

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Trametes versicolor fruit body contains protein-bound polysaccharides PSK (polysaccharide-K, krestin) and PSP (polysaccharide-peptide), and beta-D-glucans. In animal and human studies PSK and PSP stimulate T cell and NK cell proliferation, increase IL-2 and interferon-gamma expression, and have weak direct antitumour activity in vitro. In Japan PSK (Krestin) has been approved since 1977 as chemotherapy adjuvant for gastric cancer after radical surgery; included in Japanese national gastric oncology guidelines. In EU and US PSK is not registered as medicine. AEMPS does not register Trametes versicolor as medicine.

Safety

Contraindications

Pregnancy and lactation
Children under 18
Immunosuppressive therapy after organ transplantation (theoretical immune stimulation may cause rejection)
Active autoimmune disease
Mushroom allergy

Serious adverse effects

Anaphylactic reactions in mushroom-allergic patients (rare)
Transplant rejection in immunosuppressed patients (theoretical risk)
Autoimmune process activation

Common adverse effects

Nausea
Dark nail and stool discolouration (from melanins)
Allergic skin reactions

Pregnancy: can you take Turkey tail (Trametes versicolor, Coriolus versicolor)?

No RCT data in pregnancy. AEMPS does not register. Avoid in pregnancy.

Breastfeeding: can you take Turkey tail (Trametes versicolor, Coriolus versicolor)?

No data on milk transfer. Lactating women should avoid.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

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Frequently asked

What is Turkey tail (Trametes versicolor, Coriolus versicolor) used for?

Turkey tail (Trametes versicolor, Coriolus versicolor) is evaluated for the following indications with varying evidence strength: Cancer prevention through supplements (evidence tier C), Immune support and respiratory infection care (evidence tier D), Chronic fatigue (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Turkey tail (Trametes versicolor, Coriolus versicolor)?

Common side effects of Turkey tail (Trametes versicolor, Coriolus versicolor) (≥ 1 in 100): Nausea, Dark nail and stool discolouration (from melanins), Allergic skin reactions. See the Safety section for uncommon and serious reactions.

Is Turkey tail (Trametes versicolor, Coriolus versicolor) safe during pregnancy?

No RCT data in pregnancy. AEMPS does not register. Avoid in pregnancy.

Is Turkey tail (Trametes versicolor, Coriolus versicolor) compatible with breastfeeding?

No data on milk transfer. Lactating women should avoid.

Who should not take Turkey tail (Trametes versicolor, Coriolus versicolor)?

Turkey tail (Trametes versicolor, Coriolus versicolor) is contraindicated in: Pregnancy and lactation; Children under 18; Immunosuppressive therapy after organ transplantation (theoretical immune stimulation may cause rejection); Active autoimmune disease; Mushroom allergy. Full list in the Safety section.

Other drugs in this group

Urolithin A (ellagitannin metabolite, mitophagy activator), Stinging nettle root (Urtica dioica, radix), Cholecalciferol + menaquinone-7 (D3+K2 combo), Vitex agnus-castus (chasteberry, monk's pepper), Bilberry (Vaccinium myrtillus fruit extract), Eleutherococcus senticosus («Siberian ginseng»), Nicotinamide riboside (NR), Resveratrol