Ivermectin and mebendazole against cancer: New study shows effectiveness in 25 types of tumours

A new review article published on October 19, 2026, examines ivermectin and mebendazole as potential complementary cancer therapies. The authors describe a total of 37 different antitumor mechanisms of action and preclinical activity in 25 human cancers.

Particularly noteworthy are the results of a small randomized trial in metastatic colorectal cancer and an observational study using a combination of both drugs. At the same time, the authors themselves emphasize that the clinical data are still limited and that large, randomized, double-blind trials are urgently needed.

The review was published as a preprint on Zenodo. Authors include Nicolas Hulscher, James Thorp, Peter McCullough, and Harvey Risch. Affiliations include the McCullough Foundation, The Wellness Company, and the Yale School of Public Health.

🚨BREAKING: The Most Comprehensive Ivermectin–Mebendazole Cancer Paper to Date Finds 37 Distinct Anticancer Mechanisms Across 25 Human Cancer Types

We synthesized DECADES of evidence from over a HUNDRED studies, revealing one of the BROADEST repertoires of anticancer mechanisms ever documented for an off-patent drug combination:

IVERMECTIN: 29 distinct anticancer mechanisms across 20 human cancer types.

MEBENDAZOLE: 26 distinct anticancer mechanisms across 17 human cancer types.

COMBINED: 37 distinct mechanism classes across 25 human cancer types in preclinical research.

Across laboratory and animal studies, ivermectin and mebendazole have demonstrated multiple overlapping and complementary anticancer mechanisms:

Disrupt cancer-cell division
Trigger programmed cancer-cell death
Interfere with tumor energy production
Inhibit tumor blood-vessel formation
Suppress cancer-cell growth signaling
Target cancer stem-like cells
Interfere with metastatic spread
Modulate antitumor immune responses
Disrupt cancer-associated DNA repair pathways
Counter multidrug-resistance mechanisms
Enhance sensitivity to certain chemotherapies
Influence pathways involved in radiation resistance

This is a REMARKABLE breadth of anticancer mechanisms for two inexpensive, off-patent drugs—spanning nearly every major hallmark of cancer biology.

The landmark 44-page scientific paper was produced by our research team at the McCullough Foundation and The Wellness Company.

Importantly, both compounds have decades of human use, established manufacturing infrastructure, well-characterized pharmacology, and low generic-drug costs.

The data can NO LONGER be ignored. The scientific case for launching large clinical trials is stronger than ever.

In the meantime, cancer patients will continue exercising their “right to try.”

@DrHarveyRisch @McCulloughFund @twc_health @P_McCulloughMD @PeterGillooly @jathorpmfm @DrKellyVictory

— Nicolas Hulscher, MPH (@NicHulscher) October 20, 2026

Two old drugs with a surprisingly large number of mechanisms of action. Ivermectin and mebendazole are well-known, orally available anti-infectives that have been used for decades and are on the WHO list of essential medicines.

The authors searched PubMed, Europe PMC, and Google Scholar up to October 2026 for laboratory, animal, and human studies on both drugs in cancer. They identified 29 different antitumor mechanisms for ivermectin and 26 for mebendazole. After summarizing overlapping signalling pathways, 37 different classes of mechanisms of action remained.

Both substances interfere with, among others, hypoxia signalling pathways, DNA repair, angiogenesis, cancer stem cells and mechanisms of drug resistance.

The authors also describe cell cycle and mitotic inhibition, apoptosis, autophagy and immunogenic cell death as recurring effects.

Preclinical efficacy in 25 human cancer types

According to the study, ivermectin showed preclinical activity in 20 human cancers, and mebendazole in 17. Taken together, this resulted in 25 different human malignancies for which at least laboratory or animal data indicate antitumor effects.

However, preclinical results do not necessarily mean that a drug is effective in humans. Controlled clinical trials are crucial. And it is precisely at this stage that the data becomes significantly thinner.

Striking figures in metastatic colorectal cancer

Of particular note is a small randomized, double-blind, placebo-controlled study of mebendazole in metastatic colorectal cancer. Mebendazole was administered in addition to bevacizumab and FOLFOX4.

According to the review, 13 out of 20 patients (65%) in the mebendazole group achieved an objective response. In the control group, this was 2 out of 20 (10%).

A large difference was also observed in median progression-free survival: 9.25 months compared to 3.0 months. The figures are striking, but are based on only 40 patients and therefore need to be confirmed in larger studies.

Combination of ivermectin and mebendazole: 197 patients observed

A prospective observational study with 197 patients receiving a combination of ivermectin and mebendazole is even closer to addressing the actual research question of the new study. 122 patients completed a six-month follow-up period.

According to the study, 103 percent of these, or 84.4 percent respectively, achieved clinical benefit.

In 59 of the 122 patients – 48.4 percent – either no detectable tumour was found or regression was documented.

However, this was not a randomized controlled trial. Without a suitable control group, it is therefore impossible to definitively determine what proportion of the observed effect was attributable to ivermectin and mebendazole and what proportion to concurrently administered conventional cancer therapies.

Six clinical efficacy studies – three positive, two neutral

In total, the authors identified six clinical trials that examined efficacy outcomes. Of these, they evaluate:

• Three were rated positive, two neutral, and one not yet ready for final assessment.
• Four other studies primarily investigated safety, tolerability, or dosage.
• Additionally, one randomized trial is registered investigating ivermectin in combination with checkpoint immunotherapy; results are not yet available.

According to the review, no completed study using ivermectin as a sole cancer treatment exists to date.

No serious side effects of ivermectin have been documented

The authors also examined safety. A meta-analysis of patient data from 36 cancer patients who received oral ivermectin – some concurrently with chemotherapy – revealed no serious side effects attributed to the drug.

Mebendazole was used in five studies in combination with other cancer treatments. According to the authors, it was studied at very high doses.

None of the oncology studies they evaluated using either of the two drugs were discontinued due to toxicity.

The crucial limitation: Large studies are lacking

Despite the partially striking results, the authors do not conclude that ivermectin or mebendazole could already be considered established cancer therapies.

On the contrary: they explicitly call for large, prospective, double-blind, randomized parallel-group studies combining both drugs in different types of cancer.

This is crucial.

The study demonstrates broad biological plausibility, numerous preclinical findings, and initial clinical signals. However, it does not yet prove that the combination is generally effective in cancer. The authors explicitly investigate it as a complementary treatment.

Old drugs, new research question

The very fact that both active ingredients are generic, orally available, and have been known for decades makes the results interesting for research.

According to the authors, ivermectin and mebendazole have an unusually large number of different targets against tumour cells and partially complement each other because their molecular target structures do not completely overlap.

However, whether this will actually lead to an effective and widely applicable cancer therapy needs now be demonstrated in significantly larger and methodologically more rigorous clinical trials.

 

yogaesoteric
October 26, 2026