Prescriptions for ivermectin and fenbendazole surged among cancer patients after actor Mel Gibson claimed on Joe Rogan's podcast that the antiparasitic drugs cured his friends of Stage 4 cancer. The January 2025 episode has been viewed more than 13 million times on YouTube.

Research published in JAMA Network Open found the prescription rate for these drugs more than doubled among cancer patients from January through July 2025 compared to the same period the year before. No high-quality evidence supports any cancer benefit from ivermectin, and fenbendazole isn't approved for human use. The highest prescription rates appeared among men, white patients and those in the U.S. South.

Oncologists warned that patients may delay or forego effective treatments while pursuing unproven remedies. A recent Pew report found half of U.S. adults under 50 get health information from influencers and podcasters. "By the time they get to us, their cancer has progressed, and they are no longer curable," said Dr. Shikha Jain of the University of Illinois Cancer Center.