Evidence guide
Can parasites cause cancer?
Yes—certain specific parasitic infections are established cancer risks. That is very different from saying parasites cause cancer generally.
Key distinction: The U.S. National Cancer Institute identifies Opisthorchis viverrini as capable of causing cholangiocarcinoma and Schistosoma haematobium as capable of causing bladder cancer.
Which parasites matter?
Evidence is organism- and cancer-specific. Read our guides to liver flukes and bile-duct cancer and schistosomiasis and bladder cancer.
What this evidence does not establish
It does not establish that an undiagnosed parasite explains most cancers, nor that antiparasitic drugs should replace standard cancer diagnosis or treatment.
Where the book fits
The Parasite-Cancer Connection explores a much broader set of claims. Our independent book review separates established relationships from claims that require additional evidence.