Clove, Black Walnut, Wormwood and Papaya Seed

Table of Contents

1. What the Presentation Said
2. Clove Oil and Parasite Eggs
3. Clove and Eugenol Against Other Parasite Stages
4. Black Walnut: Very Little Research
5. Common Wormwood (Artemisia absinthium)
6. Papaya Seed: The Human Trials
7. Milk Thistle and Dandelion for Liver Support
8. Safety Findings
9. How the Claim Compares With the Research
10. What Is Not Known
11. Connections
12. Key Research Papers
13. Featured Videos

What the Presentation Said

In the part of the talk about treating parasites, the speaker described parasites as damaging the “terrain” in which cancer forms, and turned to what was called non-toxic natural substances. Black seed oil was described as cleansing the terrain, and clove oil was described as the substance that destroys the eggs.

The speaker's reasoning was that parasites pass through several stages and life cycles and that several mechanisms are involved in infection, so more than one or two substances are needed. A list of plant antiparasitics followed. In the machine transcript the list is partly garbled; the words that can be read are clove and black walnut, together with a word that most likely stands for papaya seeds. Later the speaker named milk thistle and dandelion as important for liver support, on the grounds that dealing with parasites can be taxing on the body.

Wormwood was not part of that herbal list. It came up later, in a passage about antiparasitic drugs studied against cancer, where the speaker said that artemisinin “is wormwood”. Wormwood is covered here because it is the usual partner of clove and black walnut in herbal parasite programmes.

No study of any of these plants was named, and no dose, product, parasite or cancer type was given. The presentation did not claim that these herbs treat cancer itself; the claim tested here is the narrower one that they act against parasites, and in particular that clove oil destroys parasite eggs.

The three-herb combination of wormwood, clove and black walnut hull, and how it became popular, is described in detail on the site's Wormwood, Clove and Black Walnut page. This page does not repeat that history; it tests the presentation's specific points.

Clove Oil and Parasite Eggs

Clove is the dried flower bud of the clove tree (Syzygium aromaticum). Its essential oil is mostly eugenol, the compound dentists use as a local anaesthetic. The claim that clove oil “destroys the eggs” can be checked against a standard laboratory method called the egg hatch test: parasite eggs collected from infected animals are placed in a dish with the test substance, and researchers count how many hatch.

What the egg hatch studies found

• In a 2002 study, eugenol and the essential oil of a basil species were tested on eggs of Haemonchus contortus, a stomach worm of goats and sheep. At a 0.50% concentration both gave the maximum inhibition of hatching (Pessoa and colleagues, 2002). This was laboratory work on eggs of a livestock worm.
• In a 2026 study, eugenol and three chemically modified versions of it were tested on the same sheep and goat worm. All of them showed ovicidal (egg-killing) and larvicidal effects in the dish, and adding an acetyl group made eugenol more potent. Electron microscopy showed damage to the outer cuticle and internal tissues of adult worms. The authors wrote that animal studies are still needed to test safety and effect (Oliveira and colleagues, 2026).

What has not been studied

No study was found in PubMed that tested clove, clove oil or eugenol against the eggs of any human intestinal worm, in the laboratory or in people. No study was found showing that clove taken by mouth reaches eggs in the human gut at the concentrations that worked in a dish. Many human parasites, including the common protozoa, do not lay eggs at all, so an egg-killing effect would not apply to them.

The laboratory finding is real but narrow: eugenol can stop eggs of a livestock stomach worm from hatching when the eggs sit in the compound. Whether that has any meaning for a person taking clove has not been tested.

Clove and Eugenol Against Other Parasite Stages

Two other kinds of study bear on clove as an antiparasitic:

• Giardia in cell culture. Clove essential oil and eugenol slowed the growth of Giardia lamblia, a gut protozoan, in culture, with half-maximal concentrations of 134 and 101 micrograms per millilitre. The oil killed almost half of the parasites over time and stopped them attaching to surfaces (Machado and colleagues, 2011).
• Schistosoma in mice. In mice infected with Schistosoma mansoni, the blood fluke behind intestinal schistosomiasis, eugenol by mouth reduced the total worm burden by 19.2%. It also lowered liver enzymes and reduced liver scarring around the fluke eggs. The authors concluded that eugenol could not totally eradicate the adult worms (El-Kady and colleagues, 2019). The comparison drug in the study was praziquantel, the standard human treatment.

No clinical trial of clove or eugenol against any parasite in people was found.

Black Walnut: Very Little Research

The black walnut (Juglans nigra) preparation used in parasite programmes is made from the green outer husk, or hull, of the nut. The hull contains juglone, a brown-staining compound of the naphthoquinone family.

• Laboratory work only. In cell culture, juglone stopped the growth of Acanthamoeba castellanii, a free-living amoeba that can infect the eye and brain, at 3–5 micromolar, by raising the production of reactive oxygen species (unstable oxygen molecules that damage cells). Adding the antioxidant N-Acetylcysteine restored the amoebae's survival (Jha and colleagues, 2015).
• No human or animal trial against parasites. No clinical trial and no animal infection study of black walnut hull against intestinal worms or protozoa was found in PubMed.
• The wood is toxic to horses. Horses bedded on shavings from black walnut trees commonly developed laminitis, a painful inflammation of the hoof; only the heartwood had this effect, and an extract of it is now used as an experimental laminitis model (Belknap, 2010). This concerns the wood, not the hull, and horses, not people.

The research base for black walnut as an antiparasitic is the thinnest of the four plants on this page. More on the plant and its safety is on the Black Walnut page and its Sources and Safety article.

Common Wormwood (Artemisia absinthium)

Common wormwood is the bitter herb of absinthe. It is a different plant from sweet wormwood (Artemisia annua), the source of the malaria drug artemisinin; the difference is explained on the sibling page Artemisinin and Artesunate in Cancer. The research on artemisinin does not transfer to common wormwood.

What the research on common wormwood shows

• In sheep. Extracts of the aerial parts of common wormwood paralysed or killed adult Haemonchus contortus worms in the dish. Given by mouth to sheep with gut roundworms, an alcohol extract at 2.0 grams per kilogram of body weight reduced the number of worm eggs in the faeces by 90.46% at day 15, which the authors described as being as effective as albendazole. A water extract was less active, at 80.49% (Tariq and colleagues, 2009).
• In people. No clinical trial of common wormwood against intestinal parasites in people was found in PubMed.

A fall in faecal egg counts in sheep given a gram-per-kilogram extract is a livestock finding. The dose was set by body weight in sheep, and the sheep worm is not a human parasite. The site's Wormwood page covers the herb more broadly; its main safety issue, thujone, is described under Safety Findings below.

Papaya Seed: The Human Trials

Papaya seed is the one plant on this page that has been tested in people against intestinal parasites. Two small trials, both in African children, were found.

Nigeria, 2007

Sixty Nigerian children with no symptoms but with parasites seen on stool microscopy were randomised to a single 20 mL dose of either an elixir of air-dried papaya seeds and honey or honey alone. Seven days later, stools were cleared of parasites in 23 of 30 children (76.7%) given the papaya elixir and in 5 of 30 (16.7%) given honey. Clearance rates for the different parasites ranged from 71.4% to 100% with papaya and 0–15.4% with honey, and no harmful effects were reported. The authors called it a pilot study and wrote that larger trials comparing papaya with a standard antiparasitic medicine were needed (Okeniyi and colleagues, 2007).

Kenya, 2018

In a study of 326 children in three primary schools in Kenya, each school formed one arm: one received porridge made with maize flour fortified with ground dried papaya seeds every day for two months, one received plain porridge, and one received plain porridge plus a single 400 mg dose of albendazole (the standard school deworming drug). Among children with roundworm (Ascaris lumbricoides), the papaya porridge reduced the mean egg count by 63.9%, against 78.8% in the albendazole arm; in the plain-porridge arm the egg count rose slightly. Haemoglobin rose more in the papaya group (Kugo and colleagues, 2018).

The design limits what this trial can show: with one school per arm, differences between schools cannot be separated from the effect of the porridge, and the trial was registered after it had started. The authors called it a preliminary survey.

Laboratory findings

• Benzyl isothiocyanate appears to be the chief or only anthelmintic compound in papaya seed, tested on the laboratory worm Caenorhabditis elegans. Water extracts of heat-treated seeds had no activity, because the plant enzyme that releases the compound had been destroyed (Kermanshai and colleagues, 2001).
• A papaya seed extract stopped 95.74% of eggs of Strongyloides venezuelensis, a rodent threadworm related to the human one, from hatching at the highest effective concentration, and stopped larvae moving as effectively as ivermectin at the top concentration, in the dish (Cabral and colleagues, 2019).

The papaya fruit itself is described on the Papaya page.

Milk Thistle and Dandelion for Liver Support

The presentation named milk thistle and dandelion for liver support during parasite treatment. No study was found that tested either plant in people being treated for parasites. The research that exists is on other liver conditions.

Milk thistle

• Cochrane review, 2007. Eighteen randomised trials in 1,088 people with alcoholic liver disease or hepatitis B or C were pooled. Milk thistle had no significant effect on overall deaths, complications of liver disease or liver tissue under the microscope. Liver-related deaths were lower when all trials were combined, but not in the high-quality trials. The reviewers wrote that their results question the benefit of milk thistle and highlight the lack of high-quality evidence; side effects were not more common than with placebo (Rambaldi and colleagues, 2007).
• Children with leukaemia, 2010. In a double-blind trial in 50 children with acute lymphoblastic leukaemia whose chemotherapy had raised their liver tests, 28 days of milk thistle or placebo made no significant difference to liver tests at day 28. At day 56 one liver enzyme (aspartate aminotransferase (AST)) was lower in the milk thistle group (P = .05). In cell culture, milk thistle did not weaken the leukaemia drugs vincristine and L-asparaginase (Ladas and colleagues, 2010). This is the cancer-care setting closest to the presentation's point, and it was a pilot study.
• Drug interactions. Silibinin, the main compound in milk thistle, blocks the drug-handling enzyme cytochrome P450 3A4 (CYP3A4) in liver cells in the laboratory. In 16 healthy men, silymarin did not meaningfully change blood levels of the test drug nifedipine; the authors concluded that it is not a potent cytochrome P450 3A4 inhibitor in the body (Fuhr and colleagues, 2007).

Dandelion

A 2025 review of dandelion (Taraxacum officinale) and the liver found that its evidence comes from animal studies, in which extracts protected the liver against alcohol, carbon tetrachloride and paracetamol. The reviewers wrote that clinical trials are still needed to confirm safety and effect in liver disease (Herrera Vielma and colleagues, 2025). No human trial of dandelion for liver protection was found.

More on both herbs is on the Milk Thistle and Dandelion pages. Liver blood tests themselves are explained on Liver Function Tests.

Safety Findings

The presentation described these substances as non-toxic. The safety literature reports the following:

Clove oil in young children

• A 7-month-old infant developed depression of the central nervous system, urinary abnormalities and a severe acid build-up in the blood (a large anion-gap acidosis) after clove oil was given by mouth by accident; the child recovered with supportive care (Lane and colleagues, 1991).
• A 2-year-old developed disseminated intravascular coagulation (widespread clotting that uses up clotting factors) and death of liver cells after swallowing clove oil (Brown and colleagues, 1992).
• A near-fatal clove-oil ingestion reported from a children's department caused coma, fits, a clotting disorder and acute liver damage, which the authors compared with the late stages of a large paracetamol overdose (Hartnoll and colleagues, 1993).

These cases involved the concentrated essential oil, not clove used as a spice.

Thujone in common wormwood

• Thujone, a compound in wormwood oil, blocks the brain's main calming receptor (gamma-aminobutyric acid-A) and causes excitation and convulsions in animals in a dose-dependent way. A 2013 toxicological review gave best estimates of allowable intake from herbal preparations and diet of about 3–7 mg of thujone a day, noted equivocal evidence of cancer in rats, and listed the human dose–effect relationship as a major gap (Pelkonen and colleagues, 2013).
• A 1997 case report in the New England Journal of Medicine described acute kidney failure caused by oil of wormwood bought over the internet (Weisbord and colleagues, 1997).

Black walnut and juglone

• Juglone is a reactive compound that kills amoebae in culture by generating oxidative stress (Jha and colleagues, 2015); no human safety study of black walnut hull taken by mouth was found.
• Black walnut heartwood causes laminitis in horses (Belknap, 2010).
• Black walnut is a tree nut, which matters for people with tree-nut allergy.

Papaya seed

The Nigerian trial reported no harmful effects after a single dose (Okeniyi and colleagues, 2007). No long-term safety study of papaya seed in people was found.

Decisions about cancer treatment and antiparasitic medicines belong with a clinician.

How the Claim Compares With the Research

• “Clove oil destroys the eggs” — supported only in the laboratory, for livestock worms. Eugenol, the main compound of clove oil, stopped eggs of a sheep and goat stomach worm from hatching in egg hatch tests. No study was found on the eggs of a human parasite or in a person taking clove.
• Clove as an antiparasitic in general — supported in part, in culture and in mice. Clove oil inhibited Giardia in culture, and eugenol cut the schistosome worm burden in mice by 19.2%, without eradicating the worms. No human trial was found.
• Black walnut — no research beyond the laboratory. Juglone kills an amoeba in culture. No animal infection study and no human trial against parasites was found.
• Wormwood — supported in livestock. An extract of common wormwood reduced faecal egg counts in sheep at gram-per-kilogram doses. No human trial was found. The presentation's statement that artemisinin “is wormwood” refers to a different plant.
• Papaya seed — supported by two small trials in children. A randomised pilot trial in Nigeria found stool clearance in 76.7% with papaya seed elixir against 16.7% with honey, and a school trial in Kenya found a 63.9% fall in roundworm egg counts against 78.8% with albendazole. Both were small, short and in endemic settings; neither compared papaya with a standard drug in a trial randomised child by child.
• Several substances for several life stages — untested. No study was found that tested a combination of these plants, or that tested the idea that different plants cover different life stages.
• Milk thistle and dandelion for liver support — not tested in parasite treatment. A Cochrane review of milk thistle in alcoholic and viral liver disease questions its benefit; a pilot trial in children with leukaemia found mixed results. Dandelion's liver evidence is from animals.
• “Non-toxic” — contradicted for the concentrated forms. Case reports describe serious clove-oil poisoning in young children and kidney failure from wormwood oil, and thujone causes convulsions in animals.
• Cancer — no research at all. No study was found that tested any of these plants against parasites in people with cancer, or that linked their use to any cancer outcome.

What Is Not Known

• Whether clove or eugenol taken by mouth affects the eggs of any human parasite.
• Whether black walnut hull has any effect on any parasite in a living animal or person.
• Whether common wormwood works against human intestinal parasites, and at what dose the thujone risk begins in people.
• How papaya seed compares with albendazole or mebendazole in a properly randomised trial, and how safe repeated use is.
• Whether any combination of these plants works better than one alone.
• Whether milk thistle or dandelion changes liver tests or outcomes during antiparasitic treatment.
• How any of these plants interacts with chemotherapy, immunotherapy or other cancer drugs in people.
• How much of each active compound commercial products contain; the plant products studied were extracts made by the researchers.

Connections

• Cancer and Parasites
• Black Seed Oil and Parasites
• Turmeric, Curcumin and Parasites
• Artemisinin and Artesunate in Cancer
• Parasite Cleanse Claims
• Wormwood, Clove and Black Walnut
• Clove
• Black Walnut
• Wormwood
• Papaya
• Milk Thistle
• Dandelion
• Ascaris
• Giardia
• Schistosoma
• Liver Function Tests

Key Research Papers

1. Pessoa LM, Morais SM, Bevilaqua CM, Luciano JH. Anthelmintic activity of essential oil of Ocimum gratissimum Linn. and eugenol against Haemonchus contortus. Vet Parasitol. 2002;109(1-2):59-63. PubMed PMID: 12383625
2. Oliveira RF, Braga AP, Barbosa MLF, et al. Synthesis, cytotoxicity and in vitro and in silico anthelmintic activity of eugenol and derivatives against Haemonchus contortus. Vet Parasitol. 2026;345:110717. PubMed PMID: 41760478
3. Machado M, Dinis AM, Salgueiro L, Custódio JB, Cavaleiro C, Sousa MC. Anti-Giardia activity of Syzygium aromaticum essential oil and eugenol: effects on growth, viability, adherence and ultrastructure. Exp Parasitol. 2011;127(4):732-9. PubMed PMID: 21272580
4. El-Kady AM, Ahmad AA, Hassan TM, El-Deek HEM, Fouad SS, Althagfan SS. Eugenol, a potential schistosomicidal agent with anti-inflammatory and antifibrotic effects against Schistosoma mansoni, induced liver pathology. Infect Drug Resist. 2019;12:709-719. PubMed PMID: 30992676
5. Jha BK, Jung HJ, Seo I, Suh SI, Suh MH, Baek WK. Juglone induces cell death of Acanthamoeba through increased production of reactive oxygen species. Exp Parasitol. 2015;159:100-6. PubMed PMID: 26358271
6. Belknap JK. Black walnut extract: an inflammatory model. Vet Clin North Am Equine Pract. 2010;26(1):95-101. PubMed PMID: 20381738
7. Tariq KA, Chishti MZ, Ahmad F, Shawl AS. Anthelmintic activity of extracts of Artemisia absinthium against ovine nematodes. Vet Parasitol. 2009;160(1-2):83-8. PubMed PMID: 19070963
8. Okeniyi JA, Ogunlesi TA, Oyelami OA, Adeyemi LA. Effectiveness of dried Carica papaya seeds against human intestinal parasitosis: a pilot study. J Med Food. 2007;10(1):194-6. PubMed PMID: 17472487
9. Kugo M, Keter L, Maiyo A, et al. Fortification of Carica papaya fruit seeds to school meal snacks may aid Africa mass deworming programs: a preliminary survey. BMC Complement Altern Med. 2018;18(1):327. PubMed PMID: 30526582
10. Kermanshai R, McCarry BE, Rosenfeld J, Summers PS, Weretilnyk EA, Sorger GJ. Benzyl isothiocyanate is the chief or sole anthelmintic in papaya seed extracts. Phytochemistry. 2001;57(3):427-35. PubMed PMID: 11393524
11. Cabral ERM, Moraes D, Levenhagen MA, Matos RAF, Costa-Cruz JM, Rodrigues RM. In vitro ovicidal and larvicidal activity of Carica papaya seed hexane extract against Strongyloides venezuelensis. Rev Inst Med Trop Sao Paulo. 2019;61:e59. PubMed PMID: 31778389
12. Rambaldi A, Jacobs BP, Gluud C. Milk thistle for alcoholic and/or hepatitis B or C virus liver diseases. Cochrane Database Syst Rev. 2007;(4):CD003620. PubMed PMID: 17943794
13. Ladas EJ, Kroll DJ, Oberlies NH, et al. A randomized, controlled, double-blind, pilot study of milk thistle for the treatment of hepatotoxicity in childhood acute lymphoblastic leukemia (ALL). Cancer. 2010;116(2):506-13. PubMed PMID: 20014183
14. Fuhr U, Beckmann-Knopp S, Jetter A, Lück H, Mengs U. The effect of silymarin on oral nifedipine pharmacokinetics. Planta Med. 2007;73(14):1429-35. PubMed PMID: 17968815
15. Herrera Vielma F, Quiñones San Martin M, Muñoz-Carrasco N, et al. The Role of Dandelion (Taraxacum officinale) in Liver Health and Hepatoprotective Properties. Pharmaceuticals (Basel). 2025;18(7):990. PubMed PMID: 40732279
16. Lane BW, Ellenhorn MJ, Hulbert TV, McCarron M. Clove oil ingestion in an infant. Hum Exp Toxicol. 1991;10(4):291-4. PubMed PMID: 1679654
17. Brown SA, Biggerstaff J, Savidge GF. Disseminated intravascular coagulation and hepatocellular necrosis due to clove oil. Blood Coagul Fibrinolysis. 1992;3(5):665-8. PubMed PMID: 1450336
18. Hartnoll G, Moore D, Douek D. Near fatal ingestion of oil of cloves. Arch Dis Child. 1993;69(3):392-3. PubMed PMID: 8215554
19. Pelkonen O, Abass K, Wiesner J. Thujone and thujone-containing herbal medicinal and botanical products: toxicological assessment. Regul Toxicol Pharmacol. 2013;65(1):100-7. PubMed PMID: 23201408
20. Weisbord SD, Soule JB, Kimmel PL. Poison on line--acute renal failure caused by oil of wormwood purchased through the Internet. N Engl J Med. 1997;337(12):825-7. PubMed PMID: 9297113

PubMed Topic Searches

1. https://pubmed.ncbi.nlm.nih.gov/?term=eugenol+egg+hatch+anthelmintic
2. https://pubmed.ncbi.nlm.nih.gov/?term=Carica+papaya+seed+intestinal+parasites
3. https://pubmed.ncbi.nlm.nih.gov/?term=Artemisia+absinthium+anthelmintic
4. https://pubmed.ncbi.nlm.nih.gov/?term=juglone+antiparasitic

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