Insufficient evidence fenbendazole cures cancer says Cancer Research UK

23 January 2023
What was claimed

Fenbendazole, the main ingredient in some dog wormers, kills almost every cancer.

Our verdict

Cancer Research UK says there’s insufficient evidence that fenbendazole can cure cancer or is safe for humans.

A post on Facebook makes the following claims: “Fun fact, pancur dog wormer kills almost every cancer, its mostly made of a drug called fenbenzadole, a drug designed to be an antibody, it kills the cells unlike your other NHS shit that just make the cells lay dormant/sleep untill they are ready to wake back up. You can buy it in pets at home. [sic]”

The dog wormer ingredient, spelt fenbendazole, is used to treat parasites in dogs.

But there isn’t sufficient evidence that it’s an effective cancer treatment for humans.

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What does fenbendazole do?

There have been some studies into fenbendazole’s potentially suppressing effect on cancer cells outside living things, and in mice. It appears to do this by stopping the proper growth of microtubules in cancer cells, which essentially provide structure to all cells. 

Although normal body cells have these microtubules, cancer cells have them too, and targeting them is already an established method of approved cancer treatments. 

However, there don’t appear to have been any studies of fenbendazole as a cancer treatment in humans. While drug studies in cells and animal models can sometimes look promising, we don’t know something will actually work (or is safe) until it is tested in humans.

Specialist cancer information nurse at Cancer Research UK, Caroline Geraghty, told Full Fact: “There is insufficient evidence that fenbendazole can cure cancer. The drug has not gone through any clinical trials to find out if it is a safe or effective treatment.

“Unsubstantiated claims that fenbendazole can cure cancer are misleading and can cause harm. Cancer patients should treat any information promoting unconventional treatments online with caution, and always discuss with their doctor before considering new therapies.”

NHS cancer therapies

The post also claims fenbendazole kills cancer cells “unlike your other NHS shit that just make the cells lay dormant/sleep untill [sic] they are ready to wake back up”.

There are several different established treatments depending on the type of cancer someone has. For example, chemotherapy works by killing cancer cells that are in the process of proliferating. How likely this is to cure someone depends on the type of cancer

While it’s true that cancer can recur (or “wake back up” as the post claims), there’s no evidence that fenbendazole would prevent recurrent cancer either, just as there isn’t sufficient evidence it can cure cancer.

In a subsequent update to the Facebook post, the user asked readers to look up the “Joe Tippens protocol”.

Joe Tippens is a man from the US who has claimed taking fenbendazole and a number of other supplements cured the cancer he was diagnosed with in 2016. However, he was also part of a clinical trial for a treatment for cancer patients at that time.

The claim that fenbendazole could cure cancer also spread in South Korea, helped in part after a comedian and singer with lung cancer claimed he was taking the drug, though he later stopped after saying it had been ineffective.

Image courtesy of the National Cancer Institute

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