Reishi and others
Also called: Ganoderma lucidum, reishi, chaga, lions mane, medicinal mushrooms.
Last reviewed 2026-09-16. How this works.
Treating cancer Grade D
No human evidence of benefit, or none that survived testing.
There is lab work and a few small studies, and nothing showing these mushrooms change a cancer.
Mechanism, and some small studies.
The claim
The claim is that medicinal mushrooms other than turkey tail act against cancer, usually argued from the polysaccharide literature that turkey tail sits in.
What it does
Mushroom polysaccharides do affect immune signalling in the laboratory. Turkey tail has its own entry because it has its own trial literature; these do not.
The evidence
A search of the trials registry returns seven completed studies across these preparations in cancer. One phase 3 trial does carry overall survival as its primary endpoint, but it tests a multi-herb formula given with chemotherapy rather than a mushroom preparation on its own.1
The other six measured depression symptoms, surgical complication rates, skin hydration, gut bacteria and quality of life. None asked what happened to a cancer.1
The harm
What has not been looked at
No completed study has reported what these preparations do to someone receiving cancer treatment. One measured surgical complication rates; the register holds no result from it.
Scope: people having cancer treatment.
Established by registry search, ClinicalTrials.gov, query intervention "reishi OR Ganoderma OR chaga OR lions mane", condition "cancer", status completed
, checked 2026-09-16. Result: no completed study reports a safety finding for these preparations alongside cancer treatment.1
What is absent
No completed trial of these mushroom preparations has measured survival, recurrence or tumour response. The one trial with a survival endpoint tests a multi-herb formula, not a mushroom.
Scope: any tumour type.
Established by registry search, ClinicalTrials.gov, query intervention "reishi OR Ganoderma OR chaga OR lions mane", condition "cancer", status completed
, checked 2026-09-16. Result: seven completed studies, none testing a mushroom preparation against a cancer outcome.1
What to ask
Is there any reason a mushroom supplement would interfere with my treatment?
The dish-to-person gap
The register holds no human pharmacokinetic measurement for these mushroom extracts against any laboratory concentration.
When to call your team — no warning signs are recorded
Whatever you are taking or thinking of taking, the people treating you can only weigh it if they know about it. That is true when nothing has been written down here, and it is most true then.
The register records no warning signs for these mushroom extracts. That is not a statement that nothing can go wrong.
Interactions
The register holds no measured interaction between these mushroom extracts and a cancer treatment class. An empty list means nobody has measured it.
Nobody having looked is not the same as nothing being there. That is what this line says and all it says.
The whole interaction list, and how to turn it into a pharmacy review request.
Find a trial instead
A trial is where a claim like this would be settled.
Search ClinicalTrials.gov for recruiting studies of Ganoderma lucidum OR reishi
A trial is the same decision with monitoring, a known preparation and a doctor who knows what else you are taking.
References
A search of the ClinicalTrials.gov registry for completed studies of these mushroom preparations in cancer, run on 16 September 2026. Seven completed studies returned.
https://clinicaltrials.gov/api/v2/studies?query.intr=reis…
How this was reached: search run during build, via a search run during the content build; not a source the manuscript carries.