Wormseed Drug Interactions, Uses, Effectiveness, Safety & More

Wormseed is an aromatic herb native to Central and South America that now grows in warm regions around the world. In cooking it is widely known as epazote and is used to flavor beans and other dishes. As a medicine, it has a long history of folk use for getting rid of intestinal worms, which is how it earned the name "wormseed."

The plant produces a pungent essential oil, sometimes called oil of chenopodium or wormseed oil. This oil was once used in both human and veterinary medicine as a deworming agent. Today it is rarely used for that purpose because it can be dangerous and because safer modern medicines exist.

The essential oil of wormseed contains a compound called ascaridole, which is thought to be responsible for its effects against worms. In laboratory studies, ascaridole appears to paralyze or kill certain parasites. The same compound is also what makes the oil potentially toxic to people.

The herb also contains other aromatic oils and plant compounds that may explain its traditional use for gas and digestion. Most of this information comes from laboratory and animal research rather than high-quality human trials, so the exact effects in people are not well proven.

Wormseed used in small amounts as a cooking herb is generally considered safe. The concern is with the concentrated essential oil and strong medicinal preparations, which can be poisonous. Historic cases of wormseed oil poisoning have caused serious harm and even death, especially in children and when doses were too high.

Pregnancy: Avoid medicinal use. Wormseed has traditionally been used to stimulate menstruation and could be harmful to a pregnancy.

Breastfeeding: Avoid medicinal use because its safety has not been established.

Children, older adults, and people with liver, kidney, or heart conditions should be especially careful. Because of the risk of toxicity, always speak with a pharmacist or doctor before using wormseed for any health purpose, and never self-treat parasites with it when safe modern medicines are available.

In small culinary amounts, wormseed rarely causes problems. Larger or medicinal amounts—especially the oil—can cause nausea, vomiting, stomach pain, dizziness, and headache.

Serious overdose has been linked to ringing in the ears, vision and hearing problems, confusion, seizures, and damage to the liver, kidneys, or heart. These severe reactions are why the oil is no longer recommended for routine use. Seek medical help right away if someone shows signs of poisoning after taking wormseed.

There is no well-established or standardized medicinal dose for wormseed, and the essential oil has a narrow margin between a useful amount and a toxic one. Because of this, we do not recommend specific amounts.

If you choose to use a wormseed product, follow the directions on the label exactly and check first with a pharmacist or doctor. As a food seasoning (epazote), the small amounts used in cooking are considered safe for most people.