Rung Five
Supplements
Unclear

Reishi mushroom

Ganoderma extracts. Herbs & mushrooms.

Verdict
UnclearThere isn't enough human evidence to say either way.
How sure
Rung 2 · LimitedFew, small or conflicting human studies, or only indirect measures such as blood markers.

The rung shows how sure the science is, not how big the effect is. How to read these ratings

Cancers affected

Lung; colorectal polyps (small studies)

What the evidence shows

Small studies of 36 and 12 people with lung cancer suggested effects on the immune system that varied from person to person. In a Japanese study of 225 people with benign colorectal tumors, the number and size of tumors fell with an extract. None of this shows it treats cancer. Turkey tail (PSK), which has stronger evidence, is rated separately.

What to do

Ask your care team before taking it; product quality varies.

Sources

To take it to your doctor, print this page.

Spotted an error? Tell us and we’ll check it against the sources.

Step by step

For the whole picture, from prevention and screening to treatment and life after, see the colorectal cancer and lung cancer pages.

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