What are the side effects of ascaridole?

October 7, 2025 •

3 min read

Ascaridole is a highly toxic chemical found in wormseed oil (oil of chenopodium), and its historical use has been largely abandoned due to severe and potentially fatal side effects. In fact, fatal cases of poisoning from ascaridole-rich oil of chenopodium have been reported, even in relatively small doses.

Quick Summary

Ascaridole, the toxic component of chenopodium oil, causes severe and potentially fatal side effects including acute gastrointestinal distress, neurological symptoms, and long-term organ damage.

Key Points

High Toxicity: Ascaridole is an extremely toxic compound that can be fatal if ingested, even in small doses.
Neurological Damage: It is a neurotoxin that can cause severe symptoms, including headache, vertigo, seizures, coma, and temporary blindness or deafness.
Multi-Organ Failure: Long-term or severe exposure can lead to significant and potentially irreversible damage to the liver, kidneys, and lungs.
Historical Dangers: Its former use as a commercial anthelmintic was largely abandoned due to a very narrow therapeutic index and the high risk of fatal poisoning.
Gastrointestinal Distress: Causes severe irritation of the digestive tract, resulting in acute nausea, vomiting, and inflammation.
Carcinogenic Potential: Evidence from rat studies suggests ascaridole may have carcinogenic properties.

Introduction to Ascaridole's Toxicity

Ascaridole is a naturally occurring organic peroxide and the primary active, and highly toxic, component of the essential oil from the Chenopodium ambrosioides plant. Traditionally, the plant was used in medicine, but by the early 1900s, concentrated oil of chenopodium rich in ascaridole was used as a vermifuge. However, its use declined due to its narrow therapeutic range and reports of severe poisoning and fatalities. Unlike herbal preparations, the concentrated oil is highly dangerous, and ingestion can lead to acute and chronic health issues.

Acute Side Effects of Ascaridole

Ingestion of ascaridole can lead to severe and rapidly escalating acute side effects. These primarily affect the gastrointestinal and central nervous systems.

Gastrointestinal System

Initial ingestion often causes severe irritation of the mouth, throat, and gastrointestinal tract, leading to:

Nausea and vomiting.
Constipation.
Gastroenteritis at high doses.

Neurological System

The central nervous system is significantly impacted, with effects ranging from mild to fatal.

Headache and vertigo.
Temporary deafness, blindness, and tinnitus.
Severe CNS depression progressing to disorientation, delirium, convulsions, and coma.

Dermatological and Sensory Reactions

Skin contact can cause irritation, and ascaridole may contribute to allergic contact dermatitis. Oil of chenopodium can also increase sensitivity to sunlight.

Chronic and Long-Term Health Consequences

Surviving acute poisoning or chronic exposure can result in lasting organ damage.

Organ Damage

Ascaridole can cause significant and potentially irreversible damage to vital organs, including:

Pulmonary edema (fluid in the lungs).
Renal damage, such as acute tubulointerstitial nephritis, hematuria, and albuminuria.
Hepatotoxicity (liver damage), including jaundice.

Carcinogenic Potential

Animal studies suggest that ascaridole may have carcinogenic properties.

Ascaridole vs. Oil of Chenopodium: A Comparison

Understanding the difference between the pure compound and the oil is important.


Feature	Ascaridole (Pure Compound)	Oil of Chenopodium (Wormseed Oil)
Source	Primary toxic component from Chenopodium ambrosioides.	Essential oil from the plant, containing ascaridole and other compounds.
Concentration	Can be purified to nearly 100%.	Variable; depends on plant and growing conditions.
Anthelmintic Action	Paralyzes worms via its 1,4 endoperoxide structure.	Paralyzes worms, mainly due to ascaridole content.
Toxicity	Highly toxic; the endoperoxide structure is the source of toxicity.	Highly toxic with a narrow therapeutic range, especially when concentrated.
Historical Usage	Basis for commercial anthelmintics, led to fatalities.	Used in traditional medicine, but concentrated oil caused fatal poisonings.

The Mechanism of Ascaridole's Toxicity

Ascaridole's toxicity is linked to its unique 1,4-endoperoxide structure. It's thought to generate reactive oxygen species (ROS) in the presence of iron, causing cellular damage and interfering with mitochondrial function. This radical generation can overwhelm the body's defenses, leading to the widespread organ damage seen in poisoning cases.

Conclusion

Ascaridole is a dangerous and highly toxic compound known for causing severe illness and death. Its historical use as an anthelmintic was discontinued due to its toxicity and narrow therapeutic window, resulting in acute gastrointestinal and neurological symptoms, as well as chronic damage to the liver, kidneys, and lungs. Its toxic effects are attributed to its chemical structure and the generation of harmful radicals. Ascaridole and concentrated oil of chenopodium should be avoided, with safer modern alternatives available for treating parasitic infections. For more on its toxicity mechanism, refer to scientific literature like studies on PubMed Central (https://pmc.ncbi.nlm.nih.gov/articles/PMC3016519/).

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Ascaridole is a toxic substance and should not be used for any medicinal purpose.

Frequently Asked Questions

Ascaridole is a toxic, organic peroxide compound and the primary active constituent of oil of chenopodium, an essential oil historically extracted from the epazote plant.

No. Ascaridole is a specific, isolated chemical compound, while oil of chenopodium is the essential oil containing ascaridole along with other substances. The oil's toxicity is largely attributed to its ascaridole content.

There is no specific antidote for ascaridole poisoning. Treatment is primarily supportive, focusing on managing the symptoms and stabilizing the patient. Emergency medical attention is required, and activated charcoal may be administered in cases of recent ingestion.

Early signs of toxicity include severe gastrointestinal irritation, such as nausea and vomiting, followed by neurological symptoms like headache, dizziness (vertigo), and tinnitus.

Ascaridole was used as a powerful anthelmintic (anti-worm) agent. However, its use was widespread during a time when safer alternatives were not available. Its high toxicity and narrow therapeutic dose eventually led to its discontinuation in favor of modern medications.

While traditional cuisine may use epazote leaves in small amounts, consuming the concentrated essential oil is highly dangerous and should be avoided. The concentration of ascaridole varies greatly, making any consumption a risk.

Ascaridole's toxicity is linked to its 1,4-endoperoxide structure. This chemical is thought to generate radicals in the presence of iron, which can damage cells and interfere with mitochondrial function in mammals.