Parasite Schmarasite:

Why the Worm Queen Trend Won't Deworm Your Real Problems

I’m overrun with patients going goo-goo ga-ga about parasites and parasite cleanses. I drafted the message below to our patients at the Leading Edge Clinic, then shared it with my partner Dr Pierre Kory and my colleague Dr Paul Marik.

Hodgkin Lymphoma cytology by Nephron

Parasite Cleanses: Straight Talk for My Patients with PASC, Vaccine Injury, or Cancer Concerns

Many of you have been asking about parasite cleanses lately—whether herbal protocols with wormwood, black walnut, clove, or papaya seeds, or even over-the-counter “deworming” kits. This topic is trending heavily on social media right now, with influencers claiming hidden parasites are causing everything from fatigue to cancer. As a clinician focused on post-acute sequelae of COVID-19 (PASC), vaccine-related injuries, and adjunctive cancer care, I want to give you clear, evidence-based guidance so you can make informed decisions.

First, the reality of parasites in the United States:
In our modern sanitation, hygiene, and food-safety environment, most Americans are not “overrun” with intestinal worms. Classic helminths (like Ascaris or hookworm) are rare outside specific risk groups—recent immigrants, international travelers, or pockets of poverty. Common exposures include Toxoplasma (often from cats or undercooked meat, usually asymptomatic) or pinworms in children. If you have no travel history, no eosinophilia on bloodwork, and no persistent unexplained diarrhea, weight loss, or abdominal pain, the chance of a significant parasitic infection is very low. True infections are diagnosed with targeted testing (stool ova-and-parasite exams, blood serologies), not assumed. (For prevalence data, see CDC resources and reviews such as Jones et al., 2014, on neglected parasitic infections: https://doi.org/10.4269/ajtmh.13-0726; Woodhall et al., 2014: https://doi.org/10.4269/ajtmh.13-0722.)Cancer and parasites:

There are rare, well-documented links—but only in specific endemic regions overseas (e.g., schistosomiasis causing bladder cancer or liver flukes linked to bile-duct cancer). These involve decades of chronic inflammation in high-risk populations. Cancer in the United States is not caused by parasites. The idea that “everyone has worms causing cancer” is simply not supported by medical evidence. (See Li et al., 2021, on repositioning antiparasitic drugs: https://doi.org/10.3389/fphar.2021.670157.)

Why certain antiparasitic drugs can still help:
This is the biggest point of confusion. Drugs like mebendazole (and its cousin fenbendazole) show promise in adjunctive cancer care because they directly disrupt microtubules inside cancer cells, halting cell division, triggering cell death (apoptosis), and cutting off blood supply to tumors. This works whether or not parasites are present—the antiparasitic effect is incidental. Key studies include Sasaki et al., 2002 (mebendazole induces mitotic arrest and apoptosis via tubulin depolymerization: https://doi.org/10.1158/1535-7163.MCT-02-1-0001) and Doudican et al., 2008 (apoptosis via Bcl-2 inactivation: https://doi.org/10.1158/1541-7786.MCR-07-2159).

Similarly, ivermectin has been used successfully by many clinicians including myself, the practitioners at the Leading Edge Clinic, and my partner Dr. Pierre Kory, author of War on Ivermectin, for symptom relief in PASC and vaccine injury. The benefits come from its powerful anti-inflammatory and immune-modulating actions—reducing cytokines, calming NF-κB pathways, and possibly interfering with spike-protein effects—not from killing parasites. (See Zaidi & Dehgani-Mobaraki, 2022, on mechanisms: https://doi.org/10.1038/s41429-021-00491-6; Portmann-Baracco et al., 2020: https://doi.org/10.1016/j.nmni.2020.100831.)

A key source of confusion is the overlap in metabolism between parasites and cancer cells. Parasites and cancer are not the same thing, and parasites are not the cause of cancer. But some antiparasitic drugs appear to affect cancer cells because both rely on overlapping survival biology—microtubules, stress signaling, redox balance, and, importantly, how they produce energy.Many parasites exist in low-oxygen environments and depend on glycolysis—a more primitive, less efficient way of generating energy through substrate-level phosphorylation rather than mitochondrial respiration. Cancer cells very often shift in that same direction (known as the Warburg effect). Even in the presence of oxygen, they rely more heavily on glycolysis and less on efficient energy production, especially as they grow and adapt under stress. (See Medjkane & Weitzman, 2013, on reversible Warburg effect in Theileria-infected cells: https://doi.org/10.1371/journal.ppat.1003686; Mudassar et al., 2020, on targeting hypoxia and mitochondrial metabolism with antiparasitics: https://doi.org/10.7150/thno.49670.)

The overlap is not causal—it is functional. Both systems lean on similar survival pathways, and drugs that disrupt those pathways may impact both. This metabolic similarity explains why certain antiparasitic agents can have off-target effects on cancer cells, independent of any actual parasitic infection.

Tapeworm, image by Mogana Das Murtey and Patchamuthu Ramasamy

What about herbal parasite cleanses?
These products have limited high-quality human evidence. Some herbs show activity against parasites in lab dishes or livestock, but well-designed studies in people are scarce and often low-quality. Recent medical reviews describe this as a social-media-driven trend with little proven benefit for the average person. Potential downsides include gastrointestinal upset (sometimes mistaken for “die-off”), medication interactions, unregulated supplement quality, and—most importantly—delaying proper evaluation of your real symptoms. In my practice, these cleanses rarely move the needle compared to addressing inflammation, mitochondrial support, or targeted therapies. (For broader context on natural products, see Ndjonka et al., 2013: https://doi.org/10.3390/ijms14023395; Strothmann et al., 2022: https://doi.org/10.1016/j.heliyon.2022.e11300.)

My practical advice:
If you have symptoms that could suggest parasites, bring them up at your visit—we can order the right tests and treat accordingly with proven medications. For the vast majority of my patients with PASC, vaccine injury, or cancer, the focus should stay on what actually drives improvement: reducing chronic inflammation, supporting detoxification pathways, optimizing immune balance, and using repurposed drugs where the science and clinical experience align. Parasite cleanses are not a shortcut or a necessary routine step.

I’m here to answer questions honestly and personalize care based on your labs, history, and response to treatment—not trends. Let’s keep the conversation going at your next appointment. Your recovery and well-being are my top priority.

— Scott Marsland, FNP-C
(With input from current medical literature, my clinical experience, and collaboration with Dr. Pierre Kory and Dr Paul Marik)

Parasite Prevalence in the US

• Jones JL, Parise ME, Fiore AE. Neglected parasitic infections in the United States: toxoplasmosis. Am J Trop Med Hyg. 2014;90(5):794-799. DOI: 10.4269/ajtmh.13-0722

• Woodhall DM, Jones JL, Cantey PT, et al. Neglected parasitic infections: what every family physician needs to know. Am Fam Physician. 2014;89(10):803-811. (PMID: 24866216; full text available via PubMed Central or journal site; no separate DOI listed in primary sources, but commonly referenced in CDC/CDC-affiliated reviews)

Cancer and Parasites / Repurposing Antiparasitic Drugs

• Li Y-Q, Zheng Z, Liu Q-X, et al. Repositioning of Antiparasitic Drugs for Tumor Treatment. Front Oncol. 2021;11:670804. DOI: 10.3389/fonc.2021.670804

Mebendazole Mechanisms in Cancer

• Sasaki J, Ramesh R, Chada S, et al. The anthelmintic drug mebendazole induces mitotic arrest and apoptosis by depolymerizing tubulin in non-small cell lung cancer cells. Mol Cancer Ther. 2002;1(13):1201-1209. (PMID: 12479701; DOI not assigned in original publication, but widely cited; full text via journal archive)

• Doudican NA, Rodriguez A, Pavlick AC, et al. Mebendazole induces apoptosis via Bcl-2 inactivation in chemoresistant melanoma cells. Mol Cancer Res. 2008;6(8):1308-1315. DOI: 10.1158/1541-7786.MCR-07-2159

Ivermectin Mechanisms (Anti-Inflammatory / Potential in Viral Contexts)

• Zaidi AK, Dehgani-Mobaraki P. The mechanisms of action of ivermectin against SARS-CoV-2—an extensive review. J Antibiot (Tokyo). 2022;75(2):60-71. DOI: 10.1038/s41429-021-00491-6

• Portmann-Baracco A, Bryce-Alberti M, Accinelli RA. Antiviral and Anti-Inflammatory Properties of Ivermectin and Its Potential Use in Covid-19. Arch Bronconeumol. 2020;56(12):831. DOI: 10.1016/j.arbres.2020.06.011

Metabolic Overlap (Warburg Effect / Glycolysis in Parasites and Cancer Cells)

• Medjkane S, Weitzman JB. A reversible Warburg effect is induced by Theileria parasites to transform host leukocytes. Cell Cycle. 2013;12(14):2167-2168. DOI: 10.4161/cc.25540

• Mudassar F, Shen H, O’Neill G, et al. Targeting tumor hypoxia and mitochondrial metabolism with anti-parasitic drugs to improve radiation response in high-grade gliomas. J Exp Clin Cancer Res. 2020;39(1):208. DOI: 10.1186/s13046-020-01724-6

Herbal / Natural Products for Antiparasitic Activity

• Ndjonka D, Rapado LN, Silber AM, et al. Natural Products as a Source for Treating Neglected Parasitic Diseases. Int J Mol Sci. 2013;14(2):3395-3439. DOI: 10.3390/ijms14023395

• Strothmann AL, et al. Antiparasitic treatment using herbs and spices: A review of the literature of the phytotherapy. Braz J Vet Med. 2022;44:e004722. DOI: 10.29374/2527-2179.bjvm004722