Breakthrough in cancer as doctor discovers pet treatment shrinks stage four tumors
A common dewormer used in dogs and cats may help cure cancer in humans, but doctors urge caution about the unproven method.
Fenbendazole, known by the brand names Panacur and Safe-Guard, is an antiparasitic agent used in animals with parasites such as roundworms, hookworms, tapeworms and Giardia.
But in recent studies examining its effectiveness in treating cancer in humans, researchers said it could be a “potentially safe and effective” alternative treatment.
In a video last month, Dr. John Campbell – a former nurse educator in Britain – discussed a review case studies 2021 showed that three patients with advanced cancer saw their tumors shrink after taking fenbendazole.
He said: ‘I think the drug regulators need to start looking at this urgently because people are dying of cancer now.
‘If something is safe and effective, it can certainly be accredited for human use quite quickly by our national licensing authorities – if they so choose.’
There have been a handful of scientific papers published in recent years showing that fenbendazole has cancer-fighting properties, including one 2020 review from scientists in Tennessee, who found that the drug slowed the growth of lung cancer in some mice with the disease.
Another study From this year, six human cases were reviewed where tumors shrank after taking the drug. The conclusion was that fenbendazole ‘stands out’ as a possible new cancer therapy.
A common dewormer used in dogs and cats may help cure cancer in humans, according to studies and anecdotal reports (stock image)
The above image shows a pack of fenbendazole for animals sold on Amazon. 2,000 purchases were made in the past month
Anecdotal reports from users on TikTok, YouTube and
But despite the growing body of evidence, medical nonprofits are currently warning against the drug’s use. They point out that it has never been tested in large-scale human clinical trials and is the gold standard for showing that a treatment is safe and effective.
And it is not without risks. Doctors in South Korea – which saw an increase in the number of people taking the drug to fight cancer in 2019 – said some patients developed intestinal necrosis, a serious medical condition in which part of the intestine dies.
In October this year, a 45-year-old British man was reported to have died of liver failure after taking the drug for its alleged cancer-fighting properties.
Dr. Jason Williams, who uses experimental treatments for cancer patients, told DailyMail.com: ‘Fenbendazole can be useful for specific content, but it is a double-edged sword.
‘In some cases, it can even promote cancer growth if not applied properly.
‘Its use should be carefully tailored to the individual patient’s situation and closely monitored.’
Fenbendazole costs about $9 for a week’s supply and is available over the counter and online for dogs in liquid, powder, or paste form.
Owners give it to pets by mixing it with the animal’s food, and veterinarians recommend a two- to three-week course of treatment to clear an infection.
It is not recommended for treating cancer in dogs, although some research and anecdotal evidence suggests it may also help cure the disease in animals.
In animals, the drug works by interfering with cell division in parasites by attacking microtubules – or the tubes that pull apart a cell nucleus to lead to cell division.
Some researchers have suggested that this may also happen in human cancer cells when someone takes the drug, slowing or stopping the progression of the disease.
Dr. John Campbell, based in Britain, posted online about the drug fenbendazole and called for more research into the treatment
The image above shows the microtubules (red lines) that pull apart a nucleus in a cell, allowing it to divide in two. Fenbendazole is said to disrupt microtubules, stopping cell division in cancer cells
Fenbendazole belongs to the class of medications called benzimidazoles, which is the same group as a human dewormer called Mebendazole.
This medication is FDA approved for deworming in humans and is available over the counter and by prescription as a chewable tablet.
It was previously sold as Vermox, available for about $2 per pill, but is now sold without insurance under the brand name Emverm for about $53 per pill.
Despite the price increase, it costs significantly less than traditional cancer treatments, which cost in the tens of thousands.
Side effects may include stomach pain and discomfort, such as bloating and gas, and diarrhea – much less serious than the hair loss, fatigue, vomiting, ulcers and infertility that result from chemotherapy.
Mebendazole has been tested as a cancer treatment in clinical trials where it had some success, including in a 2022 study in patients with advanced colon cancer, where it extended the patient’s lifespan compared to those who did not take the drug.
And inside laboratory studies that suggested it could be effective against breast cancer and brain cancer.
However, other studies have raised concerns about the drug, including: 2021 Clinical Trial involving 10 patients with advanced liver or colon cancer who received mebendazole twice daily. After eight weeks, treatment was stopped due to the progression of the cancer.
In five cases, patients had ‘hyperprogression’.
Scientists at the Williams Institute in California say they prescribe mebendazole to patients in some circumstances. In a video, a doctor from the Institute said: ‘Menbendazole, taken for what it’s worth, is an FDA-approved drug. Not fenbendazole.’
Studies on fenbendazole so far have only taken into account case studies on the use of the drug and laboratory studies, but no scientific assessment.
The above shows the cancerous pancreas of mice before (left) and after (right) they were treated with mebendazole, an antiparasitic drug approved for use in humans
Cases include an 83-year-old man with stage four lymphoma, a blood cancer, who took six pills a day for a year. Evidence showed that the patient’s cancer improved and did not spread during this period.
In another case, a 63-year-old man with advanced renal cell carcinoma started taking fenbendazole three days a week after standard treatments caused serious side effects. Scans later showed that the tumor in his left kidney had almost completely disappeared, while a tumor on his pancreas had also shrunk.
Doctors have suggested that these, as well as other cases, could be due to fenbendazole, but they emphasize that they are also anecdotal and that patients are taking other standard treatments at the same time, which may be behind the change.
The use of fenbendazole to treat cancer was first popularized by Joe Tippens of Oklahoma, who took the drug once a day for three consecutive days to fight his lung cancer.
He credited the drug with helping to reduce the disease, but at the same time he was also conducting a clinical trial for the immunotherapy drug Keytruda – which is approved to fight lung cancer.
His claims went viral in South Korea and were shared by local singer Kim Chul-min – who was also battling lung cancer.
Vets reported at the time that they were inundated with calls from people looking for doses of the drug.
The country’s Ministry of Food and Drug Safety warned at the time: ‘High doses of the drug, administered over a long period of time, can cause serious damage to the blood, nerves and liver.’
The Korean Medical Association also warned: “We cannot recommend the use of the drug as no clinical trials have been conducted on humans and its safety has not been confirmed.”
To be approved for use in humans, fenbendazole would have to undergo at least three costly clinical trials.
The above video, posted to TikTok, suggested that some people can use fenbendazole – which is available as a powder – by mixing it with olive oil
The results would then have to be evaluated by the FDA before the drug could be approved for use in humans to treat cancer.
The process would likely take years and cost more than $30 million.
Caroline Geraghty, a specialist cancer information nurse at Cancer Research UK, told DailyMail.com: ‘There is not enough evidence that fenbendazole can cure cancer.
‘The drug has not undergone clinical trials to find out whether it is a safe or effective treatment.’
She added: ‘Unsubstantiated claims that fenbendazole can cure cancer are misleading and can cause harm.
‘Cancer patients should be cautious with information promoting unconventional treatments online and always discuss this with their doctor before considering new therapies.’
Dr. Campbell resurfaced claims about the drug on YouTube, saying: ‘Of course the researchers and the writers here say further research is needed… we always need more details.
“But there you go, three patients have actually been cured of their cancer. Just read the newspaper yourself, that’s what they seem to say to me.’
Regardless, people continue to post online about the benefits of fenbendazole against cancer.
One user said on
‘I convinced him to start taking fenbendazole and apricot kernels. He was diagnosed over a year ago and is now cancer free.’
Another user said: ‘It absolutely cured my prostate cancer. The cancer had grown beyond the wall. They gave me a death sentence. I took fenbendazole. Cancer gone.”
And a third said on YouTube: ‘Fenbendazole cured my dog of ‘terminal’ squamous cell carcinoma. Fantastic stuff!
‘My dog had two months to live, I gave her fenben and 2.5 years later she is doing fine!’