As Joe Tippens watched his tumor grow in size, he became desperate. The man doctors once feared would die within days began scouring the internet, seeking solutions outside of standard cancer care. He started a regimen of CBD oil, the spice curcumin, and mega doses of vitamin E. But it was a tip from a veterinarian that, in his words, saved his life. Tippens had discovered that a drug used to rid animals of parasites could cure cancer—and that it was available without a prescription.
The wormer in question is fenbendazole, which is approved by the FDA to rid dogs and other animals of worms, including tapeworms. It’s also marketed under the brand names Safe Guard, Pro Sense, and Panacur. It’s a part of a larger class of drugs called benzimidazole anthelmintics that includes metronidazole, albendazole and albendazole, which are commonly prescribed anti-parasitic medications. The anthelmintic class of drugs has been studied for its anticancer effects in animals and humans, but only to some extent.
A number of websites, blogs and TikTok videos have been promoting the use of dog wormers as a cancer treatment. The claims have drawn skepticism from scientists and federal agencies.
According to one report, a veterinarian named Andrew Jones posted YouTube and TikTok videos in which he explains how fenbendazole was the key to curing his own small-cell lung cancer. The videos were removed, but they gained renewed popularity after resurfacing in February 2023. The videos have since been debunked by Sheila Singh, director of McMaster’s Centre for Discovery in Cancer Research.
She explains that the evidence for fenbendazole’s effectiveness against cancer is not strong enough. However, she does say that the fungus N. caninum may be able to suppress cancer growth by blocking an important pathway in cells. It may also be able to kill tumours by disrupting the structure of their internal membranes.
During his research, N. caninum was observed multiplying in tumour cells and forming vacuoles, which are compartments inside the cell. These structures allow them to escape degradation and prevent the cell from releasing enzymes that destroy them. The fungus can also “reprogram the tumour microenvironment,” which favours cancer cell growth, by decreasing the levels of molecules that encourage it to grow, such as vascular endothelial growth factor and PD-L1.
In his research, Riggins found that fenbendazole and a close relative of it, mebendazole, have similar anti-cancer effects. Like fenbendazole, mebendazole targets microtubules in cancer cells—the same kind of cell structure that provides structure to all living things. This disrupts the proper formation of these microtubules, starving cancer cells of their nutrients and potentially causing them to die. dewormer for cancer