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Mushrooms, Supplements and Cancer: What the Research Really Says

Short answer: no mushroom, herb or supplement has been shown to cure or treat cancer. The best-studied mushroom compound is PSK, a purified extract of turkey tail. In Japan it has been used for decades as an add-on to surgery and chemotherapy, and older trials suggest a modest survival benefit in some stomach and bowel cancers. That is not the same as taking a mushroom supplement from a shop, and some supplements can interfere with cancer treatment. Speak to your oncologist before you take anything.

A cancer diagnosis often sends people searching online for "natural" options. Here is what the research actually shows, and the safety questions to raise with your treatment team.

Do mushrooms like turkey tail help with cancer?

Turkey tail (Trametes versicolor) is the mushroom with the most human research behind it, but nearly all of that research used two purified, standardised extracts rather than whole-mushroom powders:

  • PSK (polysaccharide-K, also called krestin) is an approved cancer medicine in Japan. According to the US National Cancer Institute, it has been given alongside conventional cancer treatment to thousands of patients since the mid-1970s.
  • PSP (polysaccharopeptide) is a similar extract that has mostly been studied in China.

What the research shows:

  • Stomach (gastric) cancer: the National Cancer Institute summarises a 2007 meta-analysis of eight randomised trials in 8,009 patients. People who had PSK as well as chemotherapy after surgery had slightly better overall survival than people who had chemotherapy alone.
  • Bowel (colorectal) cancer: a 2022 Cochrane review pooled seven randomised trials (1,569 people, mostly in Japan and China). It found low-certainty evidence of a modest five-year survival benefit, roughly one extra survivor for every 16 people treated. The authors were uncertain whether PSK reduced side effects. They also pointed out that the chemotherapy used in these trials is now outdated and that the participants knew which treatment they were getting.
  • Other cancers: results for breast and liver cancer and for leukaemia are mixed, according to Memorial Sloan Kettering Cancer Center's integrative medicine service.

A 2026 review in Integrative and Complementary Therapies makes the key point: most of the clinical evidence comes from purified PSK or PSP, and those products may not behave like the turkey tail products sold commercially. In every trial, PSK was given alongside surgery and chemotherapy, never instead of them.

What about reishi, chaga and "mushroom blends"?

The evidence for other mushrooms is much thinner. The National Cancer Institute reports no human studies of reishi (Ganoderma lucidum) that measured cancer outcomes. Lab and animal studies are often cited online, but results in cells or mice frequently fail to carry over to people. They should never be read as proof that something works for cancer.

Can supplements interfere with chemotherapy or radiotherapy?

Yes, and many people don't realise it. Here are a few examples from authoritative sources:

  • Antioxidant supplements during chemotherapy: in a 2020 study in the Journal of Clinical Oncology, 1,134 women with breast cancer reported their supplement use. Those who took antioxidant supplements (vitamins A, C and E, carotenoids or coenzyme Q10) both before and during chemotherapy tended to have a higher risk of the cancer coming back. Vitamin B12 and iron use was also linked to poorer outcomes. This was an observational study, so it cannot prove cause and effect. The authors concluded that patients should be cautious about supplements other than a multivitamin during chemotherapy.
  • Reishi: Memorial Sloan Kettering warns that reishi may increase the risk of bleeding with blood thinners, may interfere with immunosuppressant medicines, and may affect enzymes that break down some drugs. Reishi spore powder may also raise the tumour marker CA72-4, which could confuse cancer monitoring. Liver injury from powdered reishi has been reported.
  • Turkey tail: Memorial Sloan Kettering advises people who are pregnant or breastfeeding to avoid it. Reported side effects include dark stools and darkened nails.

The US National Center for Complementary and Integrative Health puts it plainly: no complementary health approach has been shown to prevent or cure cancer, and some herbal supplements may interact harmfully with cancer drugs.

Which lifestyle factors have strong evidence?

The World Health Organization estimates that about 38% of cancers could currently be prevented by avoiding risk factors and using proven prevention measures. These are the factors with the strongest evidence:

Factor What the evidence supports
Tobacco Not smoking, and quitting at any age
Alcohol Drinking less, or not at all
Body weight and activity Staying active and keeping to a healthy weight
Diet Eating plenty of vegetables and fruit
Infections HPV vaccination and hepatitis B vaccination; cervical screening
Sun Sun protection, which matters in South Africa's strong sunlight

According to the WHO, cancer-causing infections such as HPV and hepatitis B and C caused about 10% of the cancers diagnosed worldwide in 2022, and about 30% in low- and lower-middle-income countries. This is why HPV vaccination and cervical screening matter so much in Africa.

Cancer in South Africa: the numbers

CANSA, quoting the latest National Cancer Registry report, gives the lifetime risk of a cancer diagnosis as about 1 in 7 for South African men and 1 in 8 for women. The most common cancers are prostate cancer in men and breast cancer in women, followed by cervical cancer in women. Skin cancers (basal cell and squamous cell carcinoma) are also among the most common in both sexes. Screening, such as Pap smears, breast checks and prostate discussions with your doctor, gives you the best chance of finding cancer early.

How to talk to your oncologist about supplements

  • Bring a list, or photos of the labels, of everything you take: vitamins, herbal teas, mushroom products, traditional medicines and "immune" blends.
  • Ask: "Could this interact with my chemotherapy, radiotherapy, immunotherapy or surgery?"
  • Stop or start supplements only with your team's agreement, especially in the weeks around surgery, because some herbs affect bleeding.
  • Be wary of any product or website that promises to "cure", "kill cancer cells" or "replace chemo". These claims are false, and the NCCIH specifically warns about them.

See a doctor if…

See your GP promptly about any unexplained change that lasts more than a few weeks, such as:

  • a new lump or swelling anywhere
  • unexplained weight loss or ongoing tiredness
  • a mole that changes shape, size or colour, or a sore that won't heal
  • unusual bleeding: blood in stools or urine, coughing up blood, or bleeding between periods or after menopause
  • a cough or hoarseness that won't go away, or difficulty swallowing
  • a lasting change in bowel or bladder habits

If you are having cancer treatment, follow your team's instructions about fever and infection. In an emergency, call 112 from a mobile or 10177 for an ambulance.

Support in South Africa

CANSA (the Cancer Association of South Africa) offers free information and counselling. You can call the toll-free line on 0800 22 66 22, send a WhatsApp text message to 072 197 9305 (English and Afrikaans) or 071 867 3530 (isiXhosa, isiZulu, Sesotho, Setswana and Sepedi), or email info@cansa.org.za. If you are struggling emotionally, SADAG's helpline is 0800 567 567.

For more on how we approach ingredients and evidence, see our turkey tail ingredient guide and our reishi ingredient guide, which both include safety notes.

Frequently asked questions

Can turkey tail cure cancer?

No. The purified extract PSK has been studied as an add-on to surgery and chemotherapy, mainly in Japan, and shows a modest benefit in some trials. It is not a treatment on its own, and over-the-counter supplements are not the same product.

Is it safe to take mushroom supplements during chemotherapy?

Not without checking first. Some mushrooms, such as reishi, can affect bleeding, the immune system and how drugs are broken down. Ask your oncologist or oncology pharmacist before you take any of them.

Should I take antioxidants during cancer treatment?

Only if your oncologist agrees. A 2020 study linked antioxidant supplements taken before and during chemotherapy with a higher risk of breast cancer recurrence. Getting nutrients from food is generally considered safe.

What can I do to lower my cancer risk?

Don't smoke, limit alcohol, stay active, keep to a healthy weight, eat plenty of plants, protect your skin from the sun, get vaccinated against HPV and hepatitis B, and go for recommended screening.

Where can I get free cancer support in South Africa?

Call CANSA's toll-free line on 0800 22 66 22. It offers information, counselling and referrals.

Sources

This article is for general information only and isn't medical advice. Elevate gummies are food supplements and are not intended to diagnose, treat, cure or prevent any disease. Speak to your doctor or pharmacist before starting any supplement, especially if you are pregnant, breastfeeding, taking medication or have a medical condition.

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