# Olive-wood ash lye

**Lissivio di cenere d’oliva**

**Known today as.** Lye made by steeping the ash of olive wood in river water.

Kind: Mineral

## What did Canale use it for?

The base of the bath (ch. 7).

## What does modern science say?

Lye, the alkaline liquor leached from wood ashes, was the old washing and soap-making liquid.

## Pharmacognosy and toxicology

- **potassium carbonate**: the chief alkali of wood ash
- **potassium hydroxide**: formed in the lye
- **calcium carbonate**: 

**Mechanism.** Water leached through wood ash is a caustic alkali, pH 11–13 when strong: it saponifies the skin’s oils, which is why it cleans and why a strong lye burns; in a warm bath, dilute, it is a soap. The alkalinity is the whole action.

**Dose.** Dilute, a soap; strong, a chemical burn of the skin and eyes.

**Standing.** The origin of potash and of soap; obsolete as a bath.

## What lore surrounds it?

Of the wood itself Folkard notes that “the club of Hercules, which was made of Olive-wood, took root, and became a tree,” that the club of Polyphemus “was the green trunk of an Olive-tree,” and that “the caps of the priests of Jupiter were surmounted with a twig of Olive.” The Athenians “punished with great severity those who damaged their venerated Olive,” and Pliny “asserts that the identical Olive-tree, called up by Minerva, was standing in his time.”

## Sources

- Folkard, R. (1884). *Plant Lore, Legends, and Lyrics*, “Olive.” Project Gutenberg #44638.
- Hoffmann, R. C. (2014). *An Environmental History of Medieval Europe*. Cambridge University Press.

---

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

Historical description, not medical advice.