Wormseed

Wormseed (Dysphania ambrosioides)

1. Identity

Botanical and Taxonomic Names

Dysphania ambrosioides (formerly Chenopodium ambrosioides), known as epazote, Jesuit's tea, Mexican tea, or wormseed, is an annual or short-lived perennial herb native to the Americas. The species was described in 1753 by Carl Linnaeus as Chenopodium ambrosioides. It belongs to the family Amaranthaceae (previously classified under Chenopodiaceae). The subspecies Chenopodium ambrosioides var. anthelminticum (also designated Dysphania anthelminticum) is specifically cultivated for its vermicidal properties. This subspecies is more active medicinally than the type species and is the form most often cultivated for its vermicidal activity.

Common Names

The plant is known across many languages and cultures by a wide array of names, including: apazote/epazote, mastruz (Portuguese), paico (South American Spanish), yerba de Santa María (Spanish), l'ansérine vermifuge (French), Herba Sancti Mariae, Jerusalem oak, Jesuit's tea, Mexican tea, West Indian goosefoot, sweet pigweed, worm grass, and wormzaad (Dutch). In Morocco it is locally called M'Khinza; in Assam it is known as Jilmil Sak.

Botanical Description

It is an annual or short-lived perennial herb, growing to 1.2 m (4 ft) tall, irregularly branched, with oblong-lanceolate leaves up to 12 cm long. The flowers are small and green, produced in a branched panicle at the apex of the stem. As well as in its native areas, it is grown in warm temperate to subtropical areas of Europe and the United States (Missouri, New England, Eastern US), sometimes becoming an invasive weed.

Natural Source and Geographic Range

Wormseed is native to Central and South America and the Caribbean. It is a well-known aromatic medicinal herb that has been widely employed in traditional healthcare systems in Asia, Africa, and Latin America. It is a medicinal plant found in countries with tropical, subtropical, and temperate climates, and some regions of the Mediterranean and Central America.

Common Forms and Preparations

Infusions and decoctions of the leaves, roots, and inflorescences of the herbaceous shrub have been used for centuries as dietary condiments and as traditional anthelmintics. Commercial preparations of oil of chenopodium (wormseed oil) and its active constituent, ascaridole, obtained by steam distillation, have been used with considerable success in mass treatment campaigns. The plant is also consumed fresh as a culinary herb — particularly in Mexican and Central American cuisine — dried, powdered, or made into aqueous extracts and tinctures. All aerial plant parts contain essential oil (0.7% in the leaves, 2.5% in the unripe fruits), which is composed of various monoterpenoids.

2. Traditional and Historical Use

Mesoamerican and Indigenous American Traditions

The plant's name comes from the centuries-old use of the plant by the Mayan people of Central America to treat intestinal worms. Chenopodium ambrosioides has been a cornerstone of traditional medicine in North and South America for centuries, primarily employed by indigenous peoples to expel intestinal parasites. Its use represents a significant chapter in the history of pharmacognosy, bridging traditional ethnobotanical knowledge with early 20th-century pharmacology before the advent of modern synthetic anthelmintics.

Ethnopharmacological studies in a community of Mayan subsistence farmers in Chiapas, Mexico, confirmed that decoctions containing up to 300 mg of dry plant material per kg body weight were widely used and traditionally highly regarded in the treatment of ascariasis. Across South America, various indigenous groups — including the Toba (Argentina), Mbyá-Guaraní (Paraguay), and Mapuche (Patagonia) — have documented uses of wormseed for intestinal parasites and skin disorders. In Bolivia, a root syrup of the plant has been used for influenza treatment. In Guatemala, a leaf infusion is orally taken to alleviate stomach pains.

Other Traditional Uses

Wormseed has also been used traditionally to treat asthma and dysentery and, in Europe and Northern Africa, to relieve menstrual cramps. In Morocco, where it is known as M'Khinza, it is widely used in traditional medicine to treat numerous ailments such as diabetes, digestive disorders, fever, fertility problems, immune disorders, hypertension, bronchitis, respiratory conditions, pharyngitis, cough, and flu. The plant's aerial parts have been historically employed in traditional medicine for addressing headaches, abdominal discomfort, joint issues, and respiratory disorders, alongside treatments for lice and warts.

Chenopodium has been traditionally used for digestive, respiratory, diabetic, urogenital, nervous, and vascular disorders and has anthelmintic, vermifuge, emmenagogue, sedative, antipyretic, antirheumatic, and abortifacient activities attributed to it across various folk traditions. Culinary uses include use as a condiment in soups, and the plant is said to reduce flatulence when eaten with beans.

20th-Century Pharmaceutical Use

The oil was sometimes referred to as "Baltimore Oil," because of a large production facility in Baltimore that specialized in extracting oil from the plant. Chenopodium was replaced with other, more effective and less toxic anthelmintics in the 1940s. Oil of chenopodium, or American wormseed oil, was a part of the physician's armamentarium for the treatment of intestinal parasites but could give rise to alarming toxic symptoms and death, even when given in therapeutic doses. Despite its replacement in conventional medicine, Chenopodium is still used to treat worm infections in humans in many countries.

3. Key Constituents and Active Compounds

Essential Oil Composition

Epazote essential oil contains ascaridole (up to 70%), limonene, p-cymene, and smaller amounts of numerous other monoterpenes and monoterpene derivatives including α-pinene, myrcene, terpinene, thymol, camphor, and trans-isocarveol. The precise composition varies significantly by geographic origin, chemotype, plant part, and growth stage. Ascaridole is also a major component of epazote, where it typically constitutes between 16 and 70% of the plant's essential oil. The content of ascaridole in the plant depends on cultivation and is maximal when the nitrogen-to-phosphorus ratio in the soil is about 1:4; it also changes through the year, peaking around the time when the plant seeds become mature.

Notably, some populations produce a thymol–carvacrol chemotype, dominated by oxygenated monoterpenes (56.79%), with thymol (19.45%) and carvacrol (14.30%) as the major components, a compositional profile that differs markedly from the ascaridole-rich chemotypes commonly reported in the literature.

Non-Volatile Phytochemicals

Phytochemical characterization of D. ambrosioides has revealed the presence of over 96 major bioactive compounds, including terpenoids, polyphenols, flavonoids, alkaloids, and fatty acids. A comprehensive review identified 379 compounds isolated from different species of the genus. Phenolics, flavonoids, saponins, ecdysteroids, and triterpenoids were the major classes of phytoconstituents. Around 330 chemical compounds have been identified in different plant parts, especially in its essential oil fractions (59.84%). However, only a few compounds — mainly monoterpenes and glycosides — have been isolated and fully characterized.

Ascaridole: The Principal Active Compound

Ascaridole was the first, and for a long time only, discovered naturally occurring organic peroxide. It is a natural organic compound classified as a bicyclic monoterpenoid with an unusual bridging peroxide functional group. It was isolated from chenopodium oil and named by Hüthig in 1908. Ascaridole, an asymmetric monoterpene endoperoxide with anthelmintic properties, occurs as a major constituent (60–80%) in the volatile oil of American wormseed fruit.

4. Mechanisms of Action

Anthelmintic Mechanism

Ascaridole is thought to paralyze roundworms, hookworms, and some tapeworms. Ascaridole, which constitutes more than 50% of the weight of the oil, is mainly responsible for its anthelmintic property. The biosynthesis of ascaridole is itself notable: the biosynthesis of ascaridole from the conjugated, symmetrical diene alpha-terpinene (a major component of the oil from wormseed) is catalyzed by a soluble iodide peroxidase isolated from homogenates of C. ambrosioides fruit and leaves.

Research has revealed that ascaridole is not the sole nematocidal component of the plant's infusions. Almost 90% of the nematocidal activity of Chenopodium ambrosioides infusions was due to a hydrophilic component different from ascaridole. Synthetic ascaridole and the ascaridole extracted from infusions caused a reduction of carbachol-induced contractions in rat gastrointestinal smooth muscle at concentrations required to kill Caenorhabditis elegans.

Antimalarial and Antiprotozoal Mechanisms

Ascaridole is one of the few naturally occurring endoperoxides; artemisinin, which also belongs to this group, is a potent antimalarial. Studies determined the effect of ascaridole on the in vitro development of Plasmodium falciparum; it was found to be a potent inhibitor of plasmodial growth — after 3 days, development was arrested at a drug concentration of 0.05 µM, and at 0.1 µM no parasites were visible in the culture. At lower concentrations, the effect was observed mainly at the trophozoite stage.

Cytotoxic and Mitochondrial Mechanisms

Studies on the mechanism of toxicity of the essential oil and its major pure ingredients — carvacrol, caryophyllene oxide, and ascaridole — found that all products, but especially caryophyllene oxide, inhibited the mitochondrial electron transport chain. This effect for carvacrol and caryophyllene oxide was mediated via direct complex I inhibition. Without Fe²⁺, ascaridole was less toxic to mammalian mitochondria than other major ingredients.

Anti-inflammatory Mechanism

The anti-inflammatory potential of D. ambrosioides essential oil, evaluated via the IAD (inhibition of albumin denaturation) assay, showed that, using precise nonlinear logistic models for IC₅₀ calculation, the anti-inflammatory effect of the essential oil is comparable to that of standard nonsteroidal anti-inflammatory drugs such as ibuprofen — though this comparison is in vitro only and not derived from clinical evidence.

5. Scientific Evidence by Area of Use

5.1 Anthelmintic / Antiparasitic Activity

In vitro and preclinical evidence: Chenopodium ambrosioides has been used for centuries in the Americas as a popular remedy for parasitic diseases. The essential oil of this plant possesses anthelmintic activity and is still used in some regions to treat parasitosis and leishmaniasis. In vitro studies have demonstrated nematocidal activity, and the oil has been shown to reduce the viability of helminth eggs.

Clinical field evidence (limited): Ethnopharmacological studies in a community of Mayan subsistence farmers in Chiapas, Mexico, confirmed that decoctions containing up to 300 mg of dry plant material per kg body weight were widely used and traditionally highly regarded in the treatment of ascariasis; however, therapeutic doses of up to 6,000 mg/kg of powdered, dried plant had no significant anthelmintic effect on adults of Necator, Trichuris, or Ascaris in a controlled field trial (Kliks, 1985).

Although this herbal drug was not efficacious as currently used in the field trial, its essential oil — which is highly effective — could theoretically be extracted using technology available at the village level. The plant already is known, accepted, and widely grown by rural peoples. A veterinary study found that none of the oil treatments tested in goats were effective based on statistical analyses, and the two higher oil doses (0.2 and 0.4 ml/kg body weight) caused adverse reactions. However, in in vitro tests, the oil did reduce viability of eggs and might be useful as part of a larger long-term ecological strategy.

Evidence strength: The anthelmintic effect of the whole plant / crude preparations is not established by rigorous human clinical trials. The essential oil shows in vitro and historical pharmacological efficacy, but controlled human trial data are lacking and one key field trial showed no significant effect of dried plant material in standard doses.

5.2 Anti-leishmanial Activity

In vitro evidence: In vitro studies have shown all major components (ascaridole, carvacrol, caryophyllene oxide) to be active against promastigote and amastigote forms of Leishmania, with ascaridole exhibiting the best antileishmanial activity and the essential oil showing the highest selectivity index. Studies have further demonstrated activity against Leishmania amazonensis and L. donovani.

Evidence strength: All anti-leishmanial evidence to date remains in vitro and in animal models. No human clinical trials have been conducted. Evidence is preliminary.

5.3 Antimicrobial and Antifungal Activity

The phytochemical composition of D. ambrosioides essential oil correlates directly with a demonstrated broad-spectrum antimicrobial effect against pathogenic microorganisms, positioning it as a promising natural agent for applications in the food and cosmetic industries. The oil exhibited broad-spectrum antimicrobial activity against pathogenic microorganisms such as S. aureus, E. coli, and Listeria species in laboratory assays.

Evidence strength: All antimicrobial and antifungal evidence is from in vitro laboratory studies. No human clinical trials exist. Evidence is preliminary and in vitro only.

5.4 Anti-inflammatory and Antioxidant Activity

Experimental studies have demonstrated anti-inflammatory and antioxidant activities in different experimental models. The antioxidant capacity of the oil, assessed using DPPH, HPSA, and HRSA assays, showed a clear dependence on the analytical method employed, with the highest efficacy observed in hydroxyl radical scavenging.

Dysphania ambrosioides is commonly used in traditional medicine to treat gastrointestinal disorders and fever. A study evaluated the antispasmodic and anti-inflammatory activities of its hydroethanolic extract, with antispasmodic activity evaluated on the jejunal part of the rat intestine precontracted with potassium chloride, and anti-inflammatory activity assessed both in vitro and in vivo.

Evidence strength: Antioxidant and anti-inflammatory studies are exclusively preclinical (in vitro and animal models). No human clinical data exist. Results are promising but not validated in humans.

5.5 Antimalarial Activity

Ascaridole, identified as a naturally occurring endoperoxide structurally related to artemisinin, was found to be a potent inhibitor of Plasmodium falciparum growth in vitro, with development arrested at a drug concentration of 0.05 µM after 3 days. Additional studies have investigated aqueous leaf extracts of C. ambrosioides for antimalarial potential in animal models.

Evidence strength: Exclusively in vitro and preliminary animal data. No human trials have been conducted. Evidence is interesting but very preliminary.

5.6 Anticancer Activity

Ambrosioides is rich in flavonoids and terpenoid products that have diverse pharmacological properties including antioxidant and cancer chemopreventive effects. Studies in murine (mouse) tumor models have investigated activity against Ehrlich ascitic tumor. Research has suggested its potential as an anticancer agent.

Evidence strength: All anticancer evidence is from in vitro cell lines and animal tumor models. No human clinical trials exist. Evidence is very preliminary.

5.7 Antidiabetic, Vasorelaxant, and Other Activities

Preclinical studies both in vivo and in vitro of crude extracts and essential oils from different parts of Chenopodium ambrosioides have documented anti-arthritic, acaricidal, amoebicidal, anthelmintic, anticancer, antibacterial, antidiabetic, antidiarrheal, antifertility, antifungal, anti-inflammatory, anti-leishmanial, antimalarial, anti-nociceptive, antipyretic, antioxidant, antisickling, antischistosomal, antiulcer, anxiolytic, bone regeneration, immunomodulatory, insecticidal, molluscicidal, trypanocidal, and vasorelaxant activities.

Evidence strength: The breadth of in vitro and animal research is notable; however, the absence of extensive clinical investigations and mechanistic studies remains a major limitation in the translation of experimental findings into therapeutic applications.

6. Body Systems and Health Areas

The literature associates wormseed with the following body systems and health domains:

• Gastrointestinal system: Treatment of intestinal parasites (ascariasis, hookworm, pinworm, tapeworm), dysentery, digestive disorders, flatulence, abdominal pain, and antiulcer effects.
• Immune and infectious disease: Antiparasitic (helminth, protozoa, Leishmania), antimalarial, antibacterial, antifungal, and antiviral activities documented in preclinical settings.
• Respiratory system: Traditional use for asthma, bronchitis, cough, pharyngitis, and flu.
• Reproductive / endocrine system: Traditional use as an emmenagogue (to promote menstruation) and abortifacient; associated with antifertility effects in preclinical studies.
• Cardiovascular system: Vasorelaxant and antihypertensive activity in preclinical models.
• Musculoskeletal system: Traditional use for joint pain; anti-arthritic and anti-nociceptive activities in animal studies.
• Metabolic / endocrine: Antidiabetic activity investigated in preclinical models.
• Oncology: Anticancer and antisickling activity in preclinical models.
• Nervous system: Anxiolytic and neuroprotective activities in preclinical studies; historically, neurological symptoms (dizziness, convulsions) are also associated with toxicity.

7. Dosage Forms and Reported Dosages

Wormseed has been used historically in several distinct preparations. Dosages reported in the scientific literature are as follows:

• Traditional decoctions (Mayan / Latin American use): Decoctions containing up to 300 mg of dry plant material per kg body weight were widely used and traditionally highly regarded in the treatment of ascariasis.
• Powdered dried plant (clinical field trial): Therapeutic doses of up to 6,000 mg of dry plant material per kg body weight of powdered, dried plant were tested; this dose had no significant anthelmintic effect on the adults of Necator, Trichuris, or Ascaris in the field trial.
• Essential oil (historical pharmaceutical use): As a treatment to destroy intestinal worms, 0.3 to 0.6 milliliters of the oil has been taken by mouth on an empty stomach, followed in about two hours by a laxative such as castor oil. The treatment has been repeated 10 days later.
• Veterinary oil trials: In one trial, 13 adult goats and kids with natural mixed-nematode infections were treated with 0.2 mL of oil per kg body weight. In another, kids with pure Haemonchus contortus infections were treated with single doses of oil at 0.1, 0.2, and 0.4 mL/kg body weight.
• General note: There is not enough reliable information to determine what an appropriate dose of chenopodium oil might be. It contains toxic chemicals that are unsafe.

8. Safety Considerations and Interactions

Acute and Systemic Toxicity

Wormseed is highly toxic and may be fatal when taken by mouth. Some people have died after taking less than 10 grams of the herb. Symptoms of poisoning are possible even in the low amounts used to treat parasitic infestations. These symptoms include diarrhea, vision problems, kidney problems, muscle twitching, and seizures.

Chenopodium oil contains the chemical ascaridole, which is very toxic. It can irritate the skin, mouth, throat, and lining of the stomach and intestines, and can also cause vomiting, headache, dizziness, kidney and liver damage, temporary deafness, convulsions, paralysis, and death.

Nephrotoxicity

Overdoses of wormseed oil have caused nephrotoxicity. Kidney damage has been shown in the autopsies of children who had mistakenly been given wormseed oil. Renal failure after ingesting 10 mL of wormseed oil caused the hospitalization of a 31-year-old man, who had purchased wormseed oil from a commercial provider of essential oils, mistakenly thinking he was buying absinthe. A study underscored nephrotoxicity in rats treated with C. ambrosioides leaf extract for 6 weeks, manifesting as evident necrosis in the kidney tubules. A subacute toxicity study observed a consistent increase in creatinine levels in all treated groups, suggesting a potential influence on kidney function and raising concerns about the safety of Chenopodium ambrosioides extracts regarding their long-term effects on kidney function.

Fatal Case Reports

A case of Chenopodium ambrosioides intoxication has been reported in a four-year-old girl, resulting from repeated high-dose infusions of this plant for antipyretic purposes. She was admitted to the pediatric emergency department for management of a disorder of consciousness four hours after ingesting the plant to treat acute fever. Several studies have demonstrated the effectiveness of this plant in therapeutic use, but the therapeutic range remains very limited.

Explosive and Inhalation Hazard

The oil can cause convulsions, paralysis, and death, and can also explode if heated or mixed with acids. Oil of chenopodium can cause skin reactions, and it is dangerous to inhale.

Genotoxicity

One study evaluating genetic damage induced by decoction and infusion of the plant in human lymphocyte cell cultures showed a statistical increase in the percentage of cells with chromosomal aberrations and in the frequency of sister chromatid exchanges when cultures were exposed to both preparations, and a decrease in mitotic index. These genotoxic findings in vitro raise concerns that require further investigation.

Subacute / Preclinical Toxicity (Fractions)

Acute and subacute treatments with plant fractions did not result in lethality or toxic alterations at therapeutic doses in a recent animal study, implying safety of the product at appropriate levels. However, the researchers noted that results do not entirely eliminate the need for comprehensive safety evaluations, especially in scenarios of long-term or chronic exposure.

Pregnancy and Lactation

Wormseed is not suggested in pregnant or breastfeeding women due to its toxicity. The plant's traditional attributes as an emmenagogue and abortifacient, combined with documented reproductive toxicity signals in preclinical studies, indicate a significant risk in pregnancy.

Dose Dependence of Toxicity

As for the toxicity of this plant, it is dose-dependent. Certain reports suggest the possibility of toxic effects when used at high concentrations, emphasizing the need for proper dosage standardization and detailed toxicological evaluation.

Photosensitization

Chenopodium oil might make the skin more sensitive to sunlight. Using this product together with other photosensitizing medications might increase the risk of sunburn, blistering, or rashes when the skin is exposed to sunlight.

Potential Drug Interactions

Wormseed may interact with anticancer herbs and supplements, antifungals, and antiparasitic herbs and supplements. Given the significant potency of ascaridole as an endoperoxide (structurally related to artemisinin), interactions with antiparasitic and antimalarial drugs warrant particular caution, though specific interaction studies in humans are lacking.

Confusion with Other Products

It is important to avoid confusing wormseed with chenopodium oil (wormseed oil), wormwood oil, or wormwood, which are distinct products. Wormseed is also sometimes referred to as "levant," which should not be confused with levant berry.

Overall Safety Assessment

Wormseed is toxic, and its use may result in poisoning and death. Further high-quality human study is needed before conclusions may be made on the use of American wormseed for any condition. The species necessitates further chemical studies to isolate and characterize new bioactive secondary metabolites and pharmacological investigations to clarify the mechanisms of action before clinical trials can be appropriately designed.

References

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• Wikipedia: Dysphania ambrosioides (botanical overview and essential oil composition)
• Wikipedia: Ascaridole (chemistry, history, and uses)
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