Dog Dewormer for Cancer: The Honest Evidence

"Your hope is not unreasonable. The science is real. And you don't have to walk this road alone."

- Dr Eugene Pretorius, Cancer SA Centurion

From Dr Eugene Pretorius

Patients ask me about fenbendazole and ivermectin almost every single week.

They come in with printouts, WhatsApp messages, stories of friends and family whose stage 4 cancer went into remission after taking a cheap dewormer from a pet shop. They want to know if it's real. They want to know if there's hope.

And here is what I tell them - the same thing I want you to hear today:

Your hope is not unreasonable. The science is real. And there is a clear, safe path forward.

What follows is not hype. It is not dismissal. It is the truth about three old, cheap, widely available drugs that are now at the centre of the most exciting conversation in cancer care - and how they fit into a real, powerful, personalised integrative cancer protocol in South Africa.

Read on. You are in the right place.

The Story That Changed Everything

In 2016, Joe Tippens - a businessman from Oklahoma - was diagnosed with stage 4 small-cell lung cancer. The tumours were everywhere: lungs, liver, pancreas, stomach, bladder, neck. His oncologist gave him three months.

Out of options, Joe did something unusual. On the advice of a veterinarian friend, he started taking fenbendazole - the dog dewormer you can buy at a pet shop - at 222 mg per day, three days on, four days off. He combined it with curcumin, CBD oil, and vitamin E.

A year later, his scans were clean. Every single tumour had disappeared.

Joe is still alive today. He tells his story to anyone who will listen. And the fact that he is still here, years later, is hard to ignore.

Joe's story is not alone. It is one of thousands of quiet whispers circulating in cancer communities worldwide. And the scientific establishment is finally starting to listen.

The Science: How These Old Drugs Attack Cancer

Fenbendazole, ivermectin, albendazole, and mebendazole are antiparasitic drugs that have been safely used in humans and animals for decades. In the laboratory, they do something genuinely interesting: they attack cancer cells from several different directions at the same time.

• Fenbendazole disrupts the internal "scaffolding" (microtubules) cancer cells need to divide, blocks glucose uptake by interfering with the GLUT-1 transporter and hexokinase - starving cancer of its favourite fuel - and switches on the p53 "guardian" gene that tells damaged cells to die
• Ivermectin - from the family of drugs that won the 2015 Nobel Prize in Medicine - disrupts the energy production of cancer cells and, importantly, appears to wake up the immune system against the tumour
• Albendazole (already FDA-approved for human use) chokes off the tumour's blood supply and disrupts cancer-cell division
• Mebendazole, fenbendazole's close cousin, has been the most tested in actual human cancer trials - especially for brain tumours

The Latest Peer-Reviewed Evidence (2024–2026)

This is the part that has changed the most recently. Over the last two years, a wave of new peer-reviewed studies has been published. Here is an honest summary of what they actually found - the encouraging parts and the caveats.

Fenbendazole - strong laboratory and animal evidence

• A 2025 study in Frontiers in Pharmacology showed fenbendazole triggers pyroptosis - an explosive, inflammatory form of cancer-cell death - in breast cancer cells and in mice, working through the HK2/caspase-3/GSDME pathway, with minimal toxicity to healthy tissue.¹
• A 2025 study in Translational Lung Cancer Research found that fenbendazole combined with a metabolism-targeting compound (diisopropylamine dichloroacetate) produced a synergistic anti-tumour effect against A549 lung cancer in mice - one of several papers showing fenbendazole works best in combination, not alone.²
• A 2024 BMC Cancer study confirmed fenbendazole's anticancer effect on ovarian cancer in both cell and animal models.³

Ivermectin - the first human trial and an NCI investigation

• The most important human data comes from a Phase 1/2 trial at Cedars-Sinai Medical Center, published in the Journal of Clinical Oncology (2025). It combined ivermectin with the immunotherapy drug balstilimab in metastatic triple-negative breast cancer - one of the hardest cancers to treat. In a small group of 8 evaluable, heavily pre-treated patients, the combination was safe and well tolerated, with a 37.5% clinical benefit rate at four months. In honesty: 6 of those 8 patients still progressed, and because ivermectin was given alongside approved immunotherapy, we cannot yet say how much of the benefit came from ivermectin itself. It is an encouraging early signal - not proof.⁴
• In early 2026, the US National Cancer Institute (NCI) confirmed it had run a preclinical (laboratory) study of ivermectin's "ability to kill cancer cells," with the NCI director noting there was "enough interest in it" to justify a proper look. Results are expected during 2026. This is a laboratory investigation - not yet an endorsement - but it is a striking sign that the question is being taken seriously at the highest level.⁵

Mebendazole - the one with the most human trial data

• A Phase 1 trial (Johns Hopkins) combined mebendazole with standard temozolomide in newly diagnosed high-grade brain tumours (gliomas), reporting a median overall survival of 21 months, with 41.7% of patients alive at two years - with acceptable safety at doses up to 200 mg/kg.⁶
• A Phase 1 trial in children (published in Neuro-Oncology Practice, December 2025) established the safety and maximum tolerated dose of oral mebendazole in paediatric patients with refractory or recurrent brain tumours - extending this research to the hardest childhood cancers.⁷
• A randomised Phase 2 trial (2022) tested mebendazole added to chemotherapy in recurrent glioblastoma, and a 2025 study in Cells mapped a new mechanism by which mebendazole kills ovarian cancer cells (the Girdin/AKT/NF-κB pathway).⁸
• A 2026 systematic review in the British Journal of Clinical Pharmacology pulled together the entire body of evidence on mebendazole for brain tumours - a sign this repurposed drug is now being evaluated with the same rigour as any mainstream candidate.⁹

A real-world look at ivermectin + mebendazole together

A 2026 prospective observational cohort in Anticancer Research followed 197 cancer patients taking ivermectin plus mebendazole off-label. It reported a clinical benefit ratio of 84.4%, with about half the group describing regression or no current evidence of disease. This sounds dramatic - but the authors themselves were clear that the study relied on self-reported outcomes with no control group, so the results are "hypothesis-generating" only, and urgently need randomised, placebo-controlled trials to confirm.¹⁰

Alongside these, researchers at the Anticancer Fund (Belgium) and the ReDO Project (Repurposing Drugs in Oncology) continue to systematically build the evidence base for these and other repurposed medicines.

An Honest Word on the Limits

I would be doing you a disservice if I only told you the encouraging half. So here is the honest picture, in plain language:

• Most of the strongest evidence is still in cells and animals, not large human trials. Laboratory results are a starting point, not a guarantee of what happens in a person.
• The human data we do have is small or uncontrolled - a handful of patients in the ivermectin breast-cancer trial, and a self-reported cohort with no comparison group. These generate hope and justify bigger trials; they do not prove a cure. (One widely-shared 2025 fenbendazole "case series" was in fact retracted by its journal - a reminder to weigh the source, not just the headline.)
• Fenbendazole is poorly absorbed when swallowed. A 2024 Anticancer Research review pointed out that oral fenbendazole may not reach high enough levels in the bloodstream to affect tumours - which is exactly why dose, formulation, and monitoring matter, and why buying pet-shop paste and hoping for the best is a poor strategy.¹¹
• None of these drugs is approved as a stand-alone cancer treatment. They are being studied as additions to proven care, not replacements for it.

This is not a reason to lose hope. It is a reason to do this properly, with a doctor - so you get the genuine benefit of these medicines without gambling with unproven doses or abandoning treatments that are already working for you.

The BBC Investigation - Where It Is Right, and Where It Is Imprecise

Updated 5 August 2026.

In August 2026, BBC Wales Investigates examined fenbendazole and ivermectin being sold as cancer treatments in the UK. An undercover journalist bought both without a prescription - from a stairlift salesman in south Wales, and from Amazon.

The investigation began when Rebecca Holder contacted the BBC. A salesman had come to discuss a stairlift for her father Bob, who had a brain tumour and lung cancer. Mid-conversation he changed the subject, saying he could obtain a treatment unavailable on the NHS that was known to shrink brain tumours.

It also told the story of Jared Wright, whose mother Kelly declined conventional treatment, took ivermectin and fenbendazole instead, and died. Her son described a horrible death.

We agree with the substance of it

A stairlift salesman should not be supplying prescription-only medicines to a man with a brain tumour. Nobody should buy cancer treatment from a marketplace listing. And no person with a treatable cancer should decline treatment in favour of an over-the-counter tablet.

Kelly Wright did not die because fenbendazole is uniquely dangerous. She died because she declined treatment that might have helped her. That is the lesson of this story, and we have made it throughout this article: these compounds are not a replacement for cancer treatment, and anyone presenting them as one is doing harm.

Where the reporting is imprecise: three different drugs, three different evidence bases

The programme treated these compounds largely as one category. They are not. As of August 2026 the evidence differs sharply between them, and the distinction matters.

Mebendazole has completed a human clinical trial. Researchers at Johns Hopkins ran a phase 1 study of mebendazole combined with temozolomide in 24 patients with newly diagnosed high-grade glioma, published in Neuro-Oncology Advances. Doses escalated to 200 mg/kg/day. Four patients at the highest dose developed grade 3 liver enzyme elevation in months two to five, which resolved on dose reduction or discontinuation.

It is important to be precise about what this trial was and was not. Its primary purpose was to establish the maximum tolerated dose and assess safety - and it met that goal. It was single-arm, with no control group. Survival figures were reported (median overall survival 21 months, 41.7% alive at two years), but the authors themselves are careful about them, and we will quote their caveat rather than paraphrase it:

“While a 21-month median survival and 4-year survival of 25% may sound promising, it may be difficult to reproduce this in a larger trial that focuses only on grade IV glioblastomas... survival determinations are preliminary owing to the small study size, heterogenous population (eg, inclusion of both WHO grade III and IV tumors) and sample bias.”

That caveat matters. The cohort mixed WHO grade III tumours, which carry a substantially better prognosis, with grade IV glioblastoma - so the headline survival figure is not comparable to a glioblastoma-only population. Two-thirds of patients also had high performance status. In a single-arm study of 24 people, those factors alone can produce the observed numbers. The honest reading is that safety was established and efficacy was not.

We would also note, in fairness and for consistency: one of the senior authors declared being a founder and equity holder in a company developing this compound. That interest was disclosed in the paper, which is precisely how it should work - and it stands in useful contrast to the fenbendazole case series discussed below.

Ivermectin is in an active human trial now - but it is early, small, and unfinished. The study is registered as NCT05318469, an investigator-initiated phase I/II trial at Cedars-Sinai Medical Center in Los Angeles, led by Dr Yuan Yuan. Its official title is “A Phase I/II Study Evaluating the Safety and Efficacy of Ivermectin in Combination With Immune Checkpoint Inhibitor in Patients With Metastatic Triple Negative Breast Cancer”.

The design: patients with metastatic triple-negative breast cancer who have already progressed on one to two prior lines of treatment receive oral ivermectin on days 1-3, 8-10 and 15-17 of each 21-day cycle, alongside balstilimab or pembrolizumab - both immune checkpoint inhibitors - given intravenously on day 1. The rationale comes from preclinical work suggesting ivermectin drives T-cell infiltration into breast tumours, potentially making an immunologically “cold” tumour responsive to immunotherapy.

Now the important context, taken directly from the trial registry. Estimated enrolment is 34 patients. The trial opened in October 2023, is still recruiting, and its estimated primary completion is October 2026. No results have been posted to the registry. Interim findings presented at the 2025 ASCO Annual Meeting reported the combination safe and well tolerated with an encouraging clinical benefit rate in this heavily pre-treated group, which the investigators said warranted continued investigation.

So: a real, registered, ethically approved trial at a major cancer centre - and simultaneously a small, single-site, unfinished study with no final results. Both statements are true, and anyone quoting one without the other is selling something. Separately, the National Cancer Institute began its own preclinical work on ivermectin in early 2026.

Fenbendazole is the weakest of the three, and we should say so plainly. Its evidence remains laboratory and animal work. There are no human trials. A case series describing three stage IV patients was published in Case Reports in Oncology in 2025 - and retracted by the publisher in January 2026. The retraction was not for falsified data. The retraction notice states that concerns were raised about an undeclared conflict of interest: at the time of submission, the first author “offered services related to the topic of the study,” and this was not declared in the article’s conflict-of-interest statement.

We mention that retraction deliberately, because it makes the point better than we could. The danger in this field is not the molecule. It is undisclosed interest and absent oversight. That is what the BBC documented, and it is what the retraction documented too.

We would also caution readers about the large online compilations of "hundreds of case reports" circulating on social media and advocacy websites. By the compilers' own accounting, the overwhelming majority are self-reported accounts, not published or verified cases. They are not evidence in the sense that word is normally used.

Why the trials are so few

Statements such as "no clinical evidence" are largely accurate, but they invite a false conclusion - that these compounds were tested and failed. For the most part they have not been tested in humans at all.

There is a reason, and it is economic rather than scientific. These are off-patent generic and veterinary drugs costing a few pounds. A phase III oncology trial costs tens of millions. No commercial sponsor can recover that on a molecule anyone may manufacture, so the trials go uncommissioned. Non-profit organisations such as the Anticancer Fund exist specifically to address this gap in repurposed medicine.

That is not an argument that these drugs work. It is an argument that the question remains genuinely open, and is being held open by funding rather than by findings.

What the oncology profession actually says

In fairness to every party, the position should be quoted directly and in full. In a Clinical Notice issued in May 2026, the American Society of Clinical Oncology (ASCO) strongly cautioned that ivermectin and fenbendazole should not be used for the treatment of cancer, nor as an adjunct to established cancer therapies, outside the regulatory safeguards of a well-designed clinical trial.

ASCO’s stated reasoning is that the current lack of established clinical benefit, together with the potential for toxicity and harmful drug interactions, presents an unacceptable risk. The notice states there is no robust, peer-reviewed clinical evidence that either agent is safe or effective for treating any human malignancy, and notes that a concerning number of patients are self-medicating without their oncology team’s knowledge.

We are quoting that in full, including the part about adjunct use, because readers deserve to know what the professional body says rather than a convenient half of it. We take that position seriously. It is also worth noting what the notice does and does not cover: it names ivermectin and fenbendazole. It does not address mebendazole, which has completed a phase 1 trial. And its central concern - patients self-medicating without their treating team knowing - is a concern we share entirely.

Questions the reporting leaves open

Two things are worth noting about what the published account does and does not tell us. We are working from the published article rather than the full broadcast, so this is an observation about the reporting we can see, not an assertion about what the journalists did or did not do.

No doses are reported. We are not told how much of either compound anyone took, for how long, or alongside what else. In pharmacology that is not a detail - it is the whole question. A statement that someone “took ivermectin and fenbendazole” carries about as much information as saying a patient “took a heart medication”.

The purchased products do not appear to have been analysed. An undercover journalist bought capsules from a private seller and from a marketplace listing. What was actually in them - the compound, the quantity, the purity, whether it matched the label at all - is not reported. This matters more than it might seem, and it points to a distinction worth drawing.

Veterinary medicines are not unregulated. In the UK they fall under the Veterinary Medicines Directorate, and in the United States under the FDA’s Center for Veterinary Medicine, with manufacturing standards and content requirements attached. A product bought through a third-party marketplace listing carries no equivalent assurance. The concern is not that a compound is “veterinary” - it is that an anonymous online listing tells you nothing verifiable about what is in the packet.

That is not a defence of self-medication. It is the opposite: it is another reason why obtaining medicines this way is a poor idea, and why supervision, a known source, and monitoring matter.

A note on what individual cases can and cannot show

Cancer is not one disease, and two patients with the same diagnosis on paper can have tumours that behave entirely differently. Response varies with tumour biology, mutational profile, prior treatment and much that remains poorly understood. It is why we test chemotherapy sensitivity individually rather than assume a protocol suits everyone.

That has a consequence for how any single case should be read - and it applies in both directions.

Consider what is not reported in an account of an individual patient who declines treatment and later dies: the cancer type, the stage at diagnosis, the tumour biology, the realistic prognosis with treatment, what treatment was actually offered, and what the expected outcome would have been had it been accepted. Without those, no conclusion follows about the compounds taken. It is equally possible that conventional treatment would have extended that life substantially, and that it would not have. Population statistics describe groups; they do not tell any individual what would have happened to them. That is precisely why a single outcome, however distressing, cannot establish that a therapy is worthless.

We say this with care rather than as a debating point. A family’s loss is not an argument, and we would not use it as one.

But the same standard has to hold in the other direction, and this is where we part company with much of what circulates online. If one death cannot establish that a compound does not work, then one remission cannot establish that it does. The case reports shared on social media face exactly the same limitation as any single case in a news report. Anyone citing the former as proof while dismissing the latter as meaningless is running two standards at once.

That symmetry is the entire argument for properly designed trials, and the near-absence of them for these compounds is the real problem - not a point in anyone’s favour.

Where we stand

To be direct about our own position, since readers are entitled to know it: we do evaluate antiparasitic compounds as part of a comprehensive treatment protocol at Cancer SA - never as a treatment on their own. They are one component among several, considered individually against the patient’s diagnosis, current treatment and blood work.

That distinction is not a technicality. These compounds are not used here as a monotherapy, and we would not offer them as one. Where they are appropriate, they form part of a combined protocol built around IPTLD low-dose chemotherapy, mega-dose IV Vitamin C, hyperthermia and the other elements described elsewhere on this site - selected for that patient, in that combination, for that cancer. A repurposed antiparasitic taken by itself, bought online and swallowed without monitoring, is a fundamentally different proposition from the same compound used as one part of a supervised, multi-modal protocol.

Three things define how we use them. They sit alongside active cancer treatment, never in place of it. They are monitored, with liver function and blood counts checked, because the Johns Hopkins trial showed exactly the kind of reversible hepatic toxicity that supervision detects and self-medication misses. And they are disclosed - to the patient, and to any oncologist involved in their care.

Off-label prescribing, it is worth noting, is ordinary medicine. It is lawful, it is common across oncology and paediatrics, and it rests on a doctor’s clinical judgement for an individual patient. ASCO’s position that these compounds should be used only inside a clinical trial is more restrictive than either the law or routine practice requires - and for most patients asking us about this, no such trial is open to them.

What we will not do is sequence something unproven ahead of something proven. If a patient’s concern is the toxicity of standard chemotherapy, the answer is not a dewormer bought online - it is insulin-potentiated low-dose chemotherapy, which uses the same established agents at a fraction of the dose.

The distinction that actually matters

There is a difference between a patient self-medicating with something bought online, and a patient whose doctor knows precisely what they are taking, monitors their liver function, checks it against their oncology treatment, and continues to insist on that treatment.

The first is what the BBC documented. It is dangerous, and the investigation was right to expose it. Note that the Johns Hopkins trial found reversible liver toxicity at higher doses - exactly the kind of harm that gets detected in a monitored setting and missed entirely by someone taking capsules bought from a marketplace.

The second is what integrative medicine should mean. At Cancer SA, anything of this kind sits alongside appropriate cancer care, never instead of it, with monitoring, and with full knowledge of everything else a patient is receiving. If a patient asked us to supervise them while they declined treatment that could help them, we would decline.

If you are weighing these compounds, the most valuable thing this investigation offers is not a verdict on the science. It is a warning about who you are taking your medicine, and your advice, from.

Where Repurposed Drugs Become Truly Powerful

Taken alone, fenbendazole or ivermectin is promising. Combined with the rest of an integrative cancer protocol, they become something extraordinary.

At Cancer SA, we do not use repurposed drugs in isolation. We layer them into a personalised protocol alongside our two most effective cancer treatments:

• IPTLD low-dose chemotherapy - uses insulin to open cancer cell membranes, making them dramatically more vulnerable to what comes next
• High-dose IV Vitamin C - floods the cancer cell with targeted oxidative stress while sparing healthy cells
• Repurposed drugs - then close the cancer's remaining metabolic escape routes (fenbendazole blocks glucose, ivermectin disrupts energy production, albendazole cuts off blood supply)

Four mechanisms, attacking the same cancer, at the same time. No escape.

This is the kind of layered, mechanism-driven protocol that conventional "one drug at a time" oncology simply cannot offer - and it is exactly what we do every week at Cancer SA.

Read more about IPTLD cancer treatment Read more about IV Vitamin C

What We Do at Cancer SA

When you walk into our clinic in Centurion, Pretoria, we do not offer you a one-size-fits-all protocol. We sit down with you. We listen. We look at your specific cancer, your test results, your current treatments, your goals, and your fears.

Then we build a personalised plan that combines the best of:

• IPTLD - Insulin Potentiated Targeted Low Dose chemotherapy
• High-dose IV Vitamin C therapy
• Repurposed drugs - fenbendazole, ivermectin, albendazole, mebendazole
• Ozone therapy and hyperthermia
• Chelation and heavy metal detox
• Targeted nutrition and metabolic support

All under the supervision of Dr Eugene Pretorius - MBChB (University of Pretoria), MBA, 25+ years in integrative medicine, ACAM (American College for Advancement in Medicine) certified, IPTLD trained.

This is what we do every week, for patients from across South Africa - Centurion, Pretoria, Johannesburg, Midrand, and beyond. You are not a number. You are not a file. You are a person fighting for your life, and we will fight alongside you.

Before You Explore Repurposed Drugs - Know This

If you are thinking about fenbendazole, ivermectin, or any repurposed drug - please do not do it alone. You deserve more than a social media protocol. You deserve:

• A personalised dose based on your weight, liver function, and cancer type
• Regular blood monitoring to catch side effects early
• Drug interaction screening with your existing treatments
• Proper combination with IPTLD, IV Vitamin C, and supportive therapies
• A doctor who knows this territory and walks it with you

The patients who go it alone often get a fraction of the benefit - while taking all of the risk.

You don't have to do this alone. You shouldn't. And you're not going to.

Hope is not wishful thinking. Hope, backed by science and integrative medicine, is how cancer patients take back their lives.

We would be honoured to walk this road with you.

References

1. Pan H, Jin M, Huang Q, et al. (2025). "Fenbendazole induces pyroptosis in breast cancer cells through HK2/caspase-3/GSDME signaling pathway." Frontiers in Pharmacology. PubMed Central
2. Nguyen, et al. (2025). "Synergistic anti-tumor effect of fenbendazole and diisopropylamine dichloroacetate in immunodeficient BALB/c nude mice transplanted with A549 lung cancer cells." Translational Lung Cancer Research. Translational Lung Cancer Research
3. "Transcriptome analysis reveals the anticancer effects of fenbendazole on ovarian cancer: an in vitro and in vivo study." (2024). BMC Cancer. Springer
4. A phase I/II study evaluating the safety and efficacy of ivermectin in combination with balstilimab in patients with metastatic triple-negative breast cancer. (2025). Journal of Clinical Oncology, 43(16_suppl):e13146 (Cedars-Sinai Medical Center, NCT05318469). ASCO / JCO
5. "US Cancer Institute Studying Ivermectin's Ability To Kill Cancer Cells." (Feb 2026). KFF Health News. KFF Health News
6. "Mebendazole and temozolomide in patients with newly diagnosed high-grade gliomas: results of a phase 1 clinical trial." Neuro-Oncology / PMC (Johns Hopkins). PubMed Central
7. Phan P, Stapleton SL, Riggins GJ, et al. (2025). "Phase 1 study of mebendazole therapy for refractory/progressive or recurrent pediatric brain tumors." Neuro-Oncology Practice, 12(6):1092. Oxford Academic
8. "Mebendazole plus lomustine or temozolomide in patients with recurrent glioblastoma: a randomised open-label phase II trial." (2022). PubMed Central. See also: "Mebendazole Exerts Anticancer Activity in Ovarian Cancer Cell Lines via a novel Girdin-mediated AKT/IKKα/β/NF-κB Signaling Axis." (2025). Cells. PubMed Central
9. Blum CB, et al. (2026). "From anthelmintic to neuro-oncology: A systematic review of mebendazole repurposing for brain tumour therapy." British Journal of Clinical Pharmacology. Wiley Online Library
10. "Real-world Clinical Outcomes of Ivermectin and Mebendazole in Cancer Patients: Results from a Prospective Observational Cohort." (2026). Anticancer Research, 46(6):3243. Anticancer Research
11. "Oral Fenbendazole for Cancer Therapy in Humans and Animals." (2024). Anticancer Research, 44(9):3725. Anticancer Research

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This article is for educational purposes and does not constitute medical advice. None of the drugs discussed are currently approved as monotherapy for cancer. Do not take any of these medications without consulting a qualified integrative oncology doctor. Self-medication, particularly with veterinary products, can cause serious harm. Individual results vary. At Cancer SA, we provide personalised, supervised integrative cancer care - not protocols you follow alone.