# Woodlouse

**Millepedae*, sows, slaters*

**Known today as.** Woodlice, the small crustaceans of damp places under rocks and logs, called *millepedes* in the old pharmacopoeias.

Kind: Animal

## What was it used for?

For jaundice, obstructions of the kidneys and urinary passages, and rheum falling on the eyes: dried in white wine and powdered, or steeped alive in white wine as the wine of hog-lice.

## What does modern science say?

Kept now as pets by children and by invertebrate collectors.

## Pharmacognosy and toxicology

- **calcium carbonate**: the cuticle
- **chitin**: 
- **haemocyanin**: 

**Mechanism.** The woodlouse is a crustacean whose cuticle is chitin-protein fibrils with calcium carbonate. Quincy held it diuretic and cleansing, from a nitrous salt it was thought to draw from its food.

**Dose.** Quincy gave the prepared powder from ten grains to two scruples.

**Standing.** In the London Pharmacopoeia of 1721 and in Quincy’s dispensatory of 1718.

## What lore surrounds it?

Prepared *millepedes* stayed in the London Pharmacopoeia into the eighteenth century.

## What did the older authorities say?

**Pliny.** Pliny's multipedes are the creatures “belonging to the earth-worm genus, hairy, with numerous feet, forming curves as they crawl, and contracting themselves when touched: the Greeks give to this insect the name of ‘oniscos,’ others, again, that of ‘tylos.’” The rolling-up is the woodlouse's signature, and the remedy is for the ears: “Boiled with leek-juice in a pomegranate rind, it is highly efficacious, they say, for pains in the ears; oil of roses being added to the preparation, and the mixture injected into the ear opposite to the one affected.”

## Sources

- *Pharmacopoeia Londinensis* (1721).
- Pomet, P. (1694). *Histoire générale des drogues* (English, *A Compleat History of Druggs*, 1712).
- Pliny the Elder, *Natural History* 29.39, trans. J. Bostock & H. T. Riley (1855), Perseus Digital Library.
- Wikipedia, “Woodlouse.”
- Seidl, B., et al. (2021). The dorsal tergite cuticle of *Helleria brevicornis*: ultrastructure, mineral distribution, calcite microstructure and texture. *Journal of Structural Biology: X* 5.
- Jemec Kokalj, A., et al. (2023). Proteomics of the haemolymph of the terrestrial crustacean *Porcellio scaber* reveals components of its innate immunity under baseline conditions. *Biochimie*.
- Quincy, J. (1718). *Pharmacopoeia Officinalis et Extemporanea*, “Millepedes.”

---

*Woodlouse.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-03. The Thinking Press. https://thethinkingpress.org/materia-medica/woodlouse

Historical description, not medical advice.