# Ragwort (Jacobaea vulgaris)

*Cushag (Manx); Stinking Willie*

**Known today as.** *Jacobaea vulgaris* (syn. *Senecio jacobaea*). A tall, weedy, yellow-flowered daisy of pastures and waste ground.

Kind: Plant  
Poisoning: Pyrrolizidine alkaloids (veno-occlusive disease) (https://thethinkingpress.org/materia-medica/poisons/pyrrolizidine)  
Toxic: yes

> **Caution.** Toxic to livestock, especially horses; handle with care.

## What was it used for?

None in human medicine; long known to graziers as a danger to stock.

## What does modern science say?

Ragwort contains pyrrolizidine alkaloids that cause fatal liver disease in grazing animals, especially horses, and is a serious agricultural hazard, though the bitterness of the fresh plant usually keeps animals from choosing it.

## Pharmacognosy and toxicology

- **jacobine**: a pyrrolizidine alkaloid
- **senecionine**: 
- **seneciphylline**: 
- **retrorsine**: 

**Mechanism.** The alkaloids are activated in the liver to pyrroles that cross-link DNA and proteins, killing the hepatocytes and blocking the small hepatic veins: a slow, cumulative, irreversible liver damage that kills horses and cattle months after the grazing and caused human epidemics (Jamaica, Afghanistan, South Africa) through contaminated grain and bush teas. The honey of ragwort carries the alkaloids.

**Dose.** No safe dose; the damage accumulates.

**Standing.** A notifiable weed under the UK Weeds Act 1959; no human use; the alkaloids are restricted in food by the European Union since 2020.

## What lore surrounds it?

On the Isle of Man children were taught to apologize to ragwort before pulling it up, or risk the fairies’ displeasure, and it is the Manx national flower, the cushag. In the Scottish Highlands it is “Stinking Willie,” a name tradition ties both to its smell and to William, Duke of Cumberland, whose forces are said to have spread its seed through the Highlands in horse fodder after Culloden in 1746.

## What did the older authorities say?

**Pliny.** Erigeron “is called by our people ‘senecio.’” Pliny records the toothache rite in full: “if a person, after tracing around this plant with an implement of iron, takes it up and touches the tooth affected with it three times, taking care to spit each time on the ground, and then replaces it in the same spot, so as to take root again, he will never experience any further pain in that tooth.” The plant grows “upon walls, and the tiled roofs of houses,” and the Greeks named it erigeron “because it is white in spring.” He notes the Greek writers “are by no means agreed as to this plant” and confines himself to Roman uses: the down beaten up with saffron for defluxions of the eyes, and parched with salt for scrofulous sores.

**Culpeper.** Under Venus; it “cleanses, digests, and discusses”: the decoction washes ulcers of the mouth and throat and helps the quinsy and the king’s evil, the juice heals green wounds, and an ointment of the herb boiled in old hog’s suet with mastic and olibanum is for the sciatica; “In Sussex we call it Ragweed.”

## Sources

- Plant-Lore, “Ragwort.”
- Pliny the Elder, *Natural History* 25.106, trans. J. Bostock & H. T. Riley (1855), Perseus Digital Library.
- Culpeper, N. (1653). *The Complete Herbal*, “Ragwort.” Project Gutenberg #49513.
- Stegelmeier, B. L., et al. (1999). “Pyrrolizidine alkaloid plants, metabolism and toxicity.” *Journal of Natural Toxins* 8.
- European Commission (2020). *Regulation (EU) 2020/2040 on maximum levels of pyrrolizidine alkaloids in certain foodstuffs*.

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

Historical description, not medical advice.