Unclear
Fenbendazole
a dog dewormer promoted online. Sold as cures.
Safety: Linked to drug-induced liver injury in a person taking it alongside immunotherapy.
During treatment: In a published case, it caused liver injury in a patient on immunotherapy, at first mistaken for a side effect of treatment.
- Verdict
- UnclearThere isn't enough human evidence to say either way.
- How sure
- Rung 1 · UnprovenLab or animal data only, or never directly tested in people.
The rung shows how sure the science is, not how big the effect is. How to read these ratings
Cancers affected
None shown in people
What the evidence shows
Claims come from lab studies and social media. Its safety in people hasn't been established. In a published case, an 80-year-old woman with lung cancer who took it after reading social media posts developed liver injury, which cleared once she stopped; her tumor didn't shrink.
What to do
Don't take it. Tell your care team if you have.
Sources
To take it to your doctor, print this page.
Spotted an error? Tell us and we’ll check it against the sources.
Related
Every supplement we rated, or follow one cancer step by step: breast cancer, colorectal cancer, lung cancer and prostate cancer.