According to the nonprofit organization Cancer Research UK, “There is insufficient evidence that fenbendazole cures cancer. The drug has not gone through any clinical trials and has not been proven to be safe or effective.”

In a 2019 video posted on his YouTube channel, Jones discusses the anecdotal case of Joe Tippens, who claimed that he was free of a rare form of small-cell lung cancer after taking fenbendazole for a short time. In the video, Jones mentions that Tippens also received conventional cancer treatments as part of a clinical trial and didn’t report any side effects from either of those treatments.

The video then moves on to describe a handful of studies that purport to show that fenbendazole may have anti-cancer effects in cell cultures and animals. The article cites a study of human colorectal cancer cells in which fenbendazole induced G1/S cell cycle arrest. It also cites a paper that found that the same drug reduced the growth of tumors in mice.

However, the authors of that study were careful to note that their results did not necessarily translate to humans. The authors went on to point out that the mechanism of action for fenbendazole differs from that of cytotoxic drugs, such as vinca alkaloids and taxanes, which act by blocking microtubule-associated cyclins.

The final experiment cited by the article involved three daily injections of fenbendazole 50 mg/kg/day, i.p., in BALB/cRw mice with EMT6 tumors. Whether administered alone or along with radiation, the fenbendazole treatment significantly delayed the growth of unirradiated tumors but not irradiated tumors.