A viral interview of Mel Gibson led people to ask doctors for veterinary drugs
In the months following the episode's publication, an increase was observed in the United States in the rate of combined prescriptions, meaning those given on the same day, for ivermectin and a drug from the benzimidazole family, which are veterinary drugs.
Something is changing in the public's attitude toward medicine and the medical establishment. This process is not happening all at once, but suspicion is growing. In recent years, more and more people who encounter an official medical recommendation immediately ask: who is behind it, what are their interests, and what are they hiding from me? And why should I believe a doctor specifically when there are people on the internet telling a completely different story?
The article was originally published on the Davidson Institute of Science Education website.
A large American study published in 2024 found that the percentage of adults who reported high trust in doctors and hospitals dropped from 71.5 percent in April 2020 to 40.1 percent in January 2024. This decline was born primarily against the backdrop of the coronavirus pandemic, which was not only a global health crisis but also a crisis of trust and information. As the virus spread, people turned to online sources in search of information and guidance. An article published in 2021 described how social networks, which were already serving as a central platform for social activity for millions of people who could no longer meet and talk face-to-face, also became an important source of news. In the UK, for example, the percentage of young people under 35 who used social networks for news consumption rose from 52 percent in January 2020 to 61 percent in April of that year.
Doubt in itself is not bad. Science advances thanks to questions, and good doctors should know how to explain themselves. But when skepticism toward doctors and hospitals is joined by almost blind trust in podcasts, viral videos, and celebrity testimonials, it can turn from a defense mechanism into a real danger to health.
From podcast to prescription
A real example of the erosion of trust in medicine was born following an episode of the popular podcast “The Joe Rogan Experience” in January 2025. Rogan — a host with a long and not-so-glorious history of echoing fictions — hosted actor Mel Gibson in his studio, who himself carries a long history of antisemitic conspiratorial statements. During the interview, Gibson said he had three friends who fell ill with advanced metastatic cancer (stage 4), and yet recovered. When asked how the miracle happened, Gibson claimed that the three took the drugs ivermectin and fenbendazole, which are intended for use against parasites.
The episode received millions of views, but the real story around it is not just the ratings. A new study published in JAMA Network Open found that in the months after the episode was published, there was an increase in the United States in the rate of combined prescriptions, meaning those given on the same day, for ivermectin and a drug from the benzimidazole family — which also includes fenbendazole. The increase was observed across the entire population, but was particularly prominent in diagnosed cancer patients.
Ivermectin is a popular drug for deworming horses, and it is approved for human use against certain parasitic worms or scabies, in defined dosages. During the coronavirus pandemic, there were those who claimed it was effective against the virus, even though it was found that it is not helpful in reducing the symptoms of the disease or preventing it. Fenbendazole is a veterinary drug that is not approved for human use. For several years, rumors have been circulating by word of mouth that it is effective against cancer, but in practice, there is currently no substantiated evidence that either of these two drugs is effective for treating any type of cancer in humans.
Part of the interest in these drugs stems from studies conducted on cell cultures in the laboratory or on animals engineered to simulate cancer processes, which found that they may have certain effects on processes related to cancer cells. Ivermectin has been linked in such studies to an effect on cellular signaling pathways and the death of cancer cells, especially in combination with dedicated cancer treatments. Fenbendazole affects microtubules — components of the cytoskeleton that are important for its division process.
But humans are not cell cultures or laboratory animals. Even if there were promising findings for drug trials in the laboratory, it would be impossible to conclude from them that the drug would help cancer patients, that it would extend their lives, or that it would be safe in combination with other cancer treatments.
A 2019 study, which analyzed the findings of previous clinical studies, estimated that only 3.4 percent of potential cancer drugs that reached the stage of human trials passed them successfully. Regarding ivermectin, some possible mechanisms of action were proposed by which it might act against cancerous tumors, but so far it has not been shown that it is indeed effective against cancer in practice. Clinical trials are required to check if it has any real benefit for treating humans. Regarding fenbendazole, our knowledge is even more limited: it is not approved for human use in any medical condition, and the clinical information on its safety, dosages, and effectiveness in humans is insufficient.
To check if there was a change in prescription patterns for ivermectin and drugs similar to fenbendazole, the researchers analyzed electronic medical records of more than 68 million patients in the United States. They compared the rate of prescriptions in the months of January to July 2025, after the podcast was published, to their rate in the corresponding period in 2024.
The findings were unequivocal: the rate of combined prescriptions among the entire study population almost doubled, and was 97 percent higher in 2025 compared to the year before. Among patients diagnosed with cancer, the rate of prescription recipients rose even more sharply, up to 2.63 times in the period after the podcast was published. Although the study cannot show that the podcast itself caused the increase, the findings show that the high public exposure that the treatment received was accompanied by a real change in prescription patterns in the United States, and that the change was particularly prominent in the group that the promise presented by Gibson appealed to especially strongly.
The study also has limitations. It only checked the issuance of prescriptions, and it cannot determine if the drugs were dispensed and if the patients actually took them. Also, it does not have data showing if patients took the drugs instead of accepted oncological treatment or in addition to it, or what led to the issuance of each prescription. And yet, the proximity in time and the prominent increase in the issuance of combined prescriptions to patients with cancer point to something important: when unsubstantiated medical information is distributed on a popular public platform, its consequences may exceed the boundaries of public discourse and be linked to a behavioral change that can be dangerous.
From personal story to medical promise
This story is not unique to these two drugs. The spread of wellness culture in recent years, and the growing influence of social networks on public opinion, have given personal recovery stories immense power — even when they are not backed by evidence. The mini-series “Apple Cider Vinegar” that aired on Netflix in 2025, a fictional drama based on true events, presents another example of this. The series adapts the personal story of an Australian influencer named Belle Gibson (not to be confused with Mel Gibson), who claimed that she had terminal brain cancer and cured herself through changes in diet and lifestyle. It later turned out that she was never diagnosed with cancer, so she of course did not cure herself either.
As with the great promise of ivermectin and fenbendazole, Belle Gibson's personal story drew its power largely from the way it was told: with a lot of confidence, by a charismatic storyteller. Some of these stories are also accompanied by hints that the healthcare system is supposedly hiding treatment options from the public. For people who are dealing with a serious illness and are looking for hope, such a story can sound like a lifebuoy thrown to them when they already thought they had run out of options.
The danger in unsubstantiated medical information distributed on networks is not limited to the fact that an unproven drug might not help. The bigger problem is that it might convince patients to delay effective and proven treatment or give it up, take drugs in inappropriate dosages, or combine them with other treatments without medical supervision.
It is easy to understand what is attractive about such stories. When people are dealing with a serious illness, they are not asking for complicated articles or statistical caveats. They are looking for a chance, another promising possibility, something else that perhaps they haven't tried. But in medicine, hope cannot serve as a substitute for studies that demonstrate the effectiveness and safety of a treatment. The recovery of one person following a treatment, even if it did indeed happen, does not show that the treatment is what caused it or that it will help others as well. To know if a treatment really helps, it must be tested in clinical trials: compare groups of patients, measure disease regression, survival, quality of life, and safety, and ensure that its benefit outweighs the possible harm.
Ivermectin and fenbendazole may continue to be studied in the future, like many other drugs being tested for new uses. But as of today, they are not a proven treatment for any type of cancer. The path leading from an interesting biological idea to real medical treatment passes through rigorous clinical studies, not through personal stories in podcasts and social networks, as exciting as they may be.
For more articles on the Davidson Institute of Science Education website.
