# Tansy (Tanacetum vulgare)

**Tanacetum**

**Known today as.** *Tanacetum vulgare*.

Kind: Plant  
Poisoning: Convulsant terpenes (thujone, pinocamphone, camphor) (https://thethinkingpress.org/materia-medica/poisons/convulsant-terpenes)  
Toxic: yes

> **Caution.** Poisonous in quantity.

## What was it used for?

Against worms and to provoke the menses; eaten at Easter in the “tansy” pudding.

## What does modern science say?

Its oil is rich in thujone, a nerve poison; it has caused deaths as an abortifacient. The oil is up to nine-tenths thujone, which excites the brain to convulsions, and the deaths were from women taking the oil to end pregnancies; a cup of the tea is far below that, but the herb is kept out of foods in most countries. Its old use against flies and lice has some truth: the oil repels insects in the laboratory.

## Pharmacognosy and toxicology

- **thujone**: up to 90 per cent of the oil in some chemotypes
- **camphor**: 
- **parthenolide**: 

**Mechanism.** Thujone blocks the GABA-A receptor and provokes convulsions.

**Dose.** The oil in teaspoonfuls has killed; the herb in food is restricted.

**Standing.** Thujone is limited in foods and drinks in the European Union and the United States.

## What lore surrounds it?

Its name preserves a wish: “tansy” descends through Old French and Late Latin from the Greek *athanasia*, “immortality,” most likely for the plant’s own persistence in the garden, though the coincidence with a plant so toxic in quantity has invited the darker reading.

In New England tansy was packed into coffins and rubbed on meat against the flies, and the dead were laid out on it; a tansy wreath marked a grave. Pliny’s immortality is the Greek *athanasia*, and the herb that preserved corpses may have earned the name that way.

## What did the older authorities say?

**Charlemagne and Hildegard.** The *Capitulare de villis* orders tansy grown on the imperial farms, and Hildegard of Bingen gives it for the stomach and the catarrh; the Benedictines of St Gall kept it.

**The tansy of Easter.** A pudding of eggs, cream, and tansy juice was eaten at Easter in England from the fifteenth century, in memory of the bitter herbs of Passover and to clear the body after the salt fish of Lent; Pepys ate it.

**Culpeper.** Gives it for the womb, to help conception and prevent miscarriage, and bruised and laid on the navel against worms.

## Sources

- Grieve, M. (1931). *A Modern Herbal*.
- Online Etymology Dictionary, “tansy.”
- *Capitulare de villis* (c. 800).
- Grieve, M. (1931). *A Modern Herbal*, “Tansy.”
- Höld, K. M., et al. (2000). *PNAS* 97.

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*Tansy.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-01. The Thinking Press. https://thethinkingpress.org/materia-medica/tansy

Historical description, not medical advice.