# Camphor (Cinnamomum camphora)

*Arabic *kāfūr**

**Known today as.** The crystalline gum of *Cinnamomum camphora*.

Kind: Resin & Wood  
Qualities: Cold and dry (Arabic and Galenic tradition).  
Poisoning: Convulsant terpenes (thujone, pinocamphone, camphor) (https://thethinkingpress.org/materia-medica/poisons/convulsant-terpenes)  
Toxic: yes

> **Caution.** Poisonous by mouth; seizures in children.

## What was it used for?

Cooling: against fevers and inflammations, carried against the plague, and held to quench desire.

## What does modern science say?

A counterirritant in rubs; poisonous by mouth, especially to children. From the 1870s most of the world’s camphor went into celluloid, the first plastic, and Japan and Taiwan held a near-monopoly of the natural product until it was synthesised from turpentine. By the 1930s physicians were injecting it to provoke convulsions in the treatment of schizophrenia, the first of the convulsive therapies, soon replaced by insulin and then by electricity. It survives in chest rubs at low strength; swallowed, as little as a teaspoon of the oil can kill a small child.

## Pharmacognosy and toxicology

- **camphor**: a bicyclic ketone

**Mechanism.** Camphor acts on the temperature-sensing channels of the skin: the assays show it activating TRPV3 and, only at very high concentration, blocking TRPA1. In the brain it is a convulsant.

**Dose.** About a gram has killed a small child; 50 mg per kilogram in adults.

**Standing.** Limited to 11 per cent in rubs in the United States; swallowed products withdrawn.

## What lore surrounds it?

After the Black Death camphor was carried in pomanders and burned in sickrooms as a preventive, and in the cholera years of the nineteenth century François-Vincent Raspail made it the centre of a whole system of household medicine. Camphor bags hung at the neck of schoolchildren against infection within living memory.

## What did the older authorities say?

**The Qur’an.** Promises the righteous a cup “mixed with camphor” from a spring in Paradise (76:5); in the Islamic world camphor was a scent of the blessed and of the washed dead.

**The camphor of Barus.** The earliest and dearest camphor was not from the camphor laurel at all but from *Dryobalanops* trees of Sumatra and Borneo, shipped through the port of Barus, whence the Malay *kapur barus*; Arab merchants carried it west, and Marco Polo reported its price in gold.

**Avicenna.** Counts it among the cold medicines, to be given against hot fevers and to quiet the heat of desire, which is why monks and physicians alike prescribed it as an anaphrodisiac.

## Sources

- Avicenna, *Canon of Medicine* II.
- Qur’an 76:5.
- Donkin, R. A. (1999). *Dragon’s Brain Perfume: An Historical Geography of Camphor*. Leiden: Brill.
- Love, J. N., et al. (2004). “Camphor exposure.” *Journal of Emergency Medicine* 27.

---

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

Historical description, not medical advice.