# Cuttlefish bone

**Os sepiae**

**Known today as.** The chalky internal shell of the cuttlefish, washed up on beaches.

Kind: Animal

## What was it used for?

Powdered, as a tooth powder, for spots on the eyes, and as an absorbent for the stomach.

## What does modern science say?

Mostly calcium carbonate; it is given to caged birds for the calcium. It is an ingredient in Chinese medicine.

## Pharmacognosy and toxicology

- **calcium carbonate**: aragonite, 85–90 per cent
- **chitin**: 
- **organic matrix**: 

**Mechanism.** An antacid and a mild abrasive, which is the tooth powder; the “spots on the eyes” use was abrasion of a corneal scar, a practice that would do harm. Its porous aragonite is converted to hydroxyapatite in the laboratory as a bone-graft scaffold.

**Dose.** Inert.

**Standing.** Sold for cage birds; a research biomaterial.

## What did the older authorities say?

**Dioscorides.** Gives the burnt bone for the teeth and to clean the eyes.

## Sources

- Dioscorides, *De materia medica*.
- Rocha, J. H. G., et al. (2005). “Scaffolds for bone restoration from cuttlefish.” *Bone* 37.

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*Cuttlefish bone.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-09-30. The Thinking Press. https://thethinkingpress.org/materia-medica/cuttlefish-bone

Historical description, not medical advice.