The Medical Advisor

Medically Reviewed | Last updated on July 8, 2026. Anecdotal reports and preliminary studies suggest that ivermectin and fenbendazole, both antiparasitic drugs, may have potential anticancer effects when used alongside other treatments.  Many people immediately dismiss the potential of ivermectin and fenbendazole when they learn it is “horse or dog medicine”. That initial reaction is overcome when genuine human success stories are told including the lack of serious side effects. Typically, when one adds ivermectin and mebendazole to standard cancer treatment, they might improve their outcome, meaning that the tumor shrinks faster or their cancer biomarkers, such as PSA, CA 125, or CEA drop. When this occurs in Stage 1, 2, or 3 cancers, it is sometimes difficult to tell whether it was the standard treatment, that is the surgery, chemotherapy, radiation or immunotherapy that produced the benefit. However, when the cancer has progressed to Stage 4, and particularly when it involves on...