# Rue (Ruta graveolens)

**Ruta**

**Known today as.** *Ruta graveolens*, garden rue.

Kind: Plant  
Qualities: Hot and dry in the third degree (Galen); the wild kind hotter still.  
Poisoning: Hepatotoxic monoterpenes (pulegone) (https://thethinkingpress.org/materia-medica/poisons/hepatotoxic-terpenes)  
Toxic: yes

> **Caution.** 

## What did Canale use it for?

The most frequent herb in the book: in the powder, electuary, and julep; in the bath and the anointing oils; in fumigations to expel a spirit; as an amulet; and blessed in Treatise Two, where “the devil may withdraw and tremble” wherever it is placed (chs. 5–10; Treatise Two).

## What does modern science say?

Rue was the herb of grace, a classic protection against witchcraft. Pharmacologically it is a strong irritant that causes blistering in sunlight, and in quantity induces abortion; it has no effect on spirits that can be measured.

## Pharmacognosy and toxicology

- **rutin**: 
- **bergapten**: a furanocoumarin
- **2-undecanone**: the oil

**Mechanism.** The furanocoumarins make the skin react to sunlight: blisters where the leaf touched it. The oil provokes the uterus.

**Dose.** Phytophotodermatitis from handling; the oil in quantity has caused abortion and liver damage.

**Standing.** A food flavouring in small amounts; no medicinal use.

## What lore surrounds it?

Carried against witchcraft and the evil eye across the Mediterranean; its bitterness made it the “herb of grace,” and Italian households kept the *cimaruta*, a silver charm of a rue sprig, against the *malocchio*.

## What did the older authorities say?

**Dioscorides.** Counts rue among the antidotes, against deadly drugs and the bites of serpents, and describes it for the eyes and for pains of the joints.

**Pliny.** Ranks rue among the chief medicinal plants, and tells that the antidote Pompey found among the papers of Mithridates was of rue leaves, walnuts, figs, and a pinch of salt.

## Sources

- Grieve, M. *A Modern Herbal*, “Rue.” As published on botanical.com.
- Nelson, L. S., et al. (2007). *Handbook of Poisonous and Injurious Plants*.

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*Rue.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-09-25. The Thinking Press. https://thethinkingpress.org/materia-medica/rue

Historical description, not medical advice.