# Castoreum

**Castoreum**

**Known today as.** The scent gland secretion of the beaver.

Kind: Animal

## What was it used for?

For the nerves, the womb, hysteria, and the falling sickness; in fumigations.

## What does modern science say?

Its strong smell comes in part from large amounts of phenolic compounds; it has flavoured food for at least eighty years and is used in perfumery.

## Pharmacognosy and toxicology

- **phenolic compounds**: in large amounts, part of the scent
- **nupharamine alkaloids**: 
- **oxygen-containing monoterpenes**: 

**Mechanism.** The beaver’s castor sacs hold a strong-smelling paste with which it marks its territory, its odour owed in part to large amounts of phenolic and neutral compounds.

**Dose.** Non-toxic by mouth and on the skin in animal tests; a permitted flavouring.

**Standing.** Generally recognised as safe as a food flavouring in the United States; its scent is in perfumery.

## What did the older authorities say?

**Pliny and the bestiaries.** Repeat the fable that the beaver, hunted for its castoreum, bites off its own testicles to escape; but Pliny, in another book, reports Sextius’s denial.

## Sources

- Pliny, *Natural History* VIII.
- Pliny the Elder. *Natural History* XXXII.13, trans. J. Bostock and H. T. Riley (1855). Perseus Digital Library.
- Badke, D. *The Medieval Bestiary*: “Beaver: source texts.” bestiary.ca.
- Burdock, G. A. (2007). Safety assessment of castoreum extract as a food ingredient. *International Journal of Toxicology* 26: 51–55.
- Tang, R., Webster, F. X., and Müller-Schwarze, D. (1993). Phenolic compounds from male castoreum of the North American beaver, *Castor canadensis*. *Journal of Chemical Ecology* 19: 1491–1500.
- Tang, R., Webster, F. X., and Müller-Schwarze, D. (1995). Neutral compounds from male castoreum of North American beaver, *Castor canadensis*. *Journal of Chemical Ecology* 21: 1745–1762.
- Stoye, A., et al. (2009). Stereoselective synthesis of enantiomerically pure nupharamine alkaloids from castoreum. *Angewandte Chemie International Edition* 48: 2228–2230.

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

Historical description, not medical advice.