No, cancer is not a parasite, and ivermectin can’t cure it

Years after some people falsely touted ivermectin as a supposed wonder drug to treat COVID-19, social media posts are claiming that the antiparasitic drug is a cure for cancer.

A Facebook post said that research "confirms the true nature of cancer is a parasite, hence why, Ivermectin, in conjunction with mebendazole, and (fenbendazole) is so effective. It targets the parasite, not the whole body, like in chemo." 

The post further stated that "cancer is a parasite: The cure, is an anti-parasitical." 

The post was flagged as part of Meta’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Meta, which owns Facebook, Instagram and Threads.)

Mebendazole and fenbendazole are both antiparasitic drugs, as is ivermectin. 

The post is wrong about cancer and misleading about the drugs’ effectiveness in treating it. Cancer shares some properties with parasites, but it is not a parasite.

Cancer arises from cell mutations in a person’s body; it’s not a separate organism. These  mutations are inherited, develop randomly, or are caused by a person’s environment. A parasite is a separate organism that lives on or in another host organism and derives nutrients from it. 

Cancer shares most of its DNA with the person who has it, with some mutations. Parasites, like roundworms or tapeworms, have a completely different DNA from the host they enter. 

Cancer and parasites both grow or reproduce by drawing resources from the host and can resist the host’s immune responses. 

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The post’s claim that ivermectin and other antiparasitics can "cure" cancer is also unproven. Neither the FDA nor the World Health Organization have approved ivermectin to treat cancer, but some studies have shown it can slow tumor growth in research settings. 

The Facebook post linked to a study called "Ivermectin: a multifaceted drug with a potential beyond anti-parasitic therapy," published in March in Cureus, an academic journal. The study refers to several other studies that have shown ivermectin may inhibit tumor growth. 

But the Facebook post overstated the drug’s effectiveness. The study it linked to said "extensive in vivo (live) studies and clinical trials are crucial to translating preclinical observations into therapeutic benefits for humans," and it cautioned against self-medicating with ivermectin. 

Although some studies have shown ivermectin can slow tumor growth in research settings, it has not been extensively studied in humans. In studies, researchers have written  that more research needs to be done about the drug’s potential role in cancer treatment, and exactly how it could inhibit cancer growth.

Whether the body could tolerate doses of the drug at a high enough level to work is a key question that researchers haven’t determined, one study said. 

None of the studies involved testing the drug on humans, and the authors did not claim the drug should replace chemotherapy or other cancer treatment drugs. 

"These studies are preclinical studies which means they have not gone through the thorough study and testing required to show that they are effective and safe in humans," said Skyler Johnson, a radiation oncology professor at the University of Utah’s Huntsman Cancer Institute. 

None of the available research, Johnson added, "supports the claim that Ivermectin is an effective treatment for cancer."

Mebendazole and fenbendazole, the other drugs the post mentioned, have also exhibited anticancer properties in early research, but like ivermectin, have not been studied in humans.

We rate the claim that cancer is a parasite, and ivermectin can be used to treat it, False.