A benzimidazole anthelmintic drug, fenbendazole is used to treat parasitic infestations such as worms. It is also known to prevent the recurrence of certain sexually transmitted infections such as Cryptococcus neoformans (a fungus that exists in all environments and causes meningitis). It has recently been discovered that fenbendazole is capable of altering many molecular pathways in cancer cells, including disrupting proteasomal interference, inhibiting microtubule function, and preventing glucose absorption. This discovery has sparked interest in using fenbendazole for humans as an alternative treatment to conventional cancer therapies. However, there is no clinical proof that fenbendazole has cancer-fighting properties and it has not gone through the required testing in human subjects. The claim that fenbendazole can cure cancer was first made in 2016 by a US man named Joe Tippens who claimed that the drug along with a number of supplements had cured him of small cell lung cancer, melanoma, and stage 4 pancreatic cancer. He went on to create a website and Facebook page where he shares his story and encourages others to take the drug for their own ailments. While these claims may be appealing to people with cancer, experts have dismissed them as unsubstantiated. A specialist cancer information nurse at Cancer Research UK told Full Fact that despite the claims of patients, “There is no evidence that fenbendazole can ‘cure’ cancer.” The drug has never been tested in human trials and has not been proven to be effective as a cancer treatment. In addition to its proteasomal interference and microtubule-inhibiting effects, fenbendazole has also been shown to interfere with the ability of cancer cells to absorb glucose, effectively starving them. This has been shown to reduce tumor growth and promote regression in cancer patients with large B-cell lymphoma, renal cell carcinoma, and metastatic disease. This was achieved by inhibiting the transporter isoform 4 (GLUT4) from being transported into the cell membrane to absorb glucose, causing insulin-fueled sugar absorption to decrease in the cells. Furthermore, fenbendazole has been shown to interact with tubulin to inhibit its movement. This is similar to the way that colchicine works, a common chemotherapy medication that inhibits microtubule formation, thus stopping cells from growing and proliferating. In another study, fenbendazole was found to inhibit GLUT4 expression in colorectal cancer cells and suppress RAS-related signaling in KRAS-mutant colon cancer cells. This suggests that fenbendazole has the potential to enhance the effectiveness of other cancer therapies such as radiation treatment, surgery, berberine, and sodium dichloroacetate (DCA). While these results are promising, more studies are needed in order to confirm the claims of some individuals that fenbendazole is an effective cancer therapy. Until then, it is important to talk to your doctor about the possible side effects of fenbendazole before beginning treatment.