# Caper spurge (Euphorbia lathyris)

**Latiri*; *cataputia minore**

**Known today as.** *Euphorbia lathyris*.

Kind: Plant  
Poisoning: Gastrointestinal irritants (https://thethinkingpress.org/materia-medica/poisons/gastrointestinal)  
Toxic: yes

> **Caution.** 

## What did Canale use it for?

Eight or ten seeds whole in an egg, or leaves in broth, as a vomit; its milky sap only with great care (ch. 5; note XXXVII).

## What does modern science say?

The seeds are purgative, the root purgative and emetic, the milky juice acrid, and the leaves blister. Canale’s warning about the sap is sound.

## Pharmacognosy and toxicology

- **ingenol**: 
- **phorbol esters**: 

**Mechanism.** The diterpene esters activate protein kinase C and inflame skin and gut.

**Dose.** A few seeds purge violently; the latex blisters and blinds.

**Standing.** Ingenol mebutate, from a related spurge, was licensed for actinic keratosis in 2012 and withdrawn in Europe in 2020.

## What lore surrounds it?

Thiselton-Dyer has the spurges among the devil's plants, “the spurge having long been named ‘devil's milk,’” the sun-spurge nicknamed cat's-milk “from its milky juice oozing in drops, as milk from the small teats of a cat,” and in Scotland “a popular cure for ringworm” being a decoction of sun-spurge, “or, as it is locally termed, ‘mare's milk.’”

## What did the older authorities say?

**Pliny.** Describes the lathyris, with leaves like the lettuce and buds whose seed is enclosed “in envelopes like that of the caper”: the seeds, about the size of a peppercorn, “white, sweet, and easily cleansed from the husk,” twenty of them taken in water or hydromel “are curative of dropsy, and carry off bile,” and those who need a stronger purgative take more.

## Sources

- Pliny the Elder, *Natural History* 27.71, trans. J. Bostock & H. T. Riley (1855), Perseus Digital Library.
- Thiselton-Dyer, T. F. (1889). *The Folk-lore of Plants*. Project Gutenberg #10118.
- Nelson, L. S., et al. (2007). *Handbook of Poisonous and Injurious Plants*.

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

Historical description, not medical advice.