camphor
Meaning of camphor: The smell of a chest rub, and one of the few household remedies that regularly sends small children to an emergency department.
Definition of camphor
Camphor is a strong smelling waxy compound taken from the wood of the camphor laurel or made synthetically from turpentine. Rubbed on the skin it produces a cooling then warming sensation and eases itching, and its vapor gives chest rubs their characteristic smell. Swallowed, even in small amounts, it acts as a poison that can cause seizures.
How does it work on the skin?
By stimulating nerve endings rather than by treating tissue. Camphor activates the receptors that report cold and, at higher concentrations, those that report warmth, which produces the familiar cool then hot sensation. That sensory noise competes with itch and with aching, and competing with a sensation is what a counterirritant does; it substitutes one feeling for another instead of reducing inflammation. Its topical preparations are therefore aimed at symptoms, and the mild germ killing action of the compound is a secondary property rather than the reason for using it.
Why is swallowing it dangerous?
It crosses into the brain quickly and in high concentration, where it excites nerve cells. Vomiting, agitation and confusion come first, and a seizure can follow within minutes of swallowing, sometimes as the first sign of trouble. Small children are at particular risk because the quantity involved is small and these products sit in bathrooms and bedrooms rather than locked away. No antidote exists, and regulators in several countries cap how much camphor a product sold without prescription may contain.
What is it found in?
| Product type | Role of camphor |
|---|---|
| Chest and vapor rubs | Aromatic sensation with a mild counterirritant effect |
| Muscle rubs and liniments | Counterirritant alongside menthol and methyl salicylate |
| Anti-itch preparations | Damps itch by competing sensation |
| Mothballs and repellents | Insect repellent, in products that are not medicines |
The last row explains a recurring source of poisoning, since a camphor mothball resembles a sweet and belongs in no medicine cabinet.
How does it compare with similar plant oils?
Camphor sits with menthol, eucalyptus oil and tea tree oil in a group of aromatic plant compounds that act on sensation and share a pattern: tolerated on intact skin at low concentration, and toxic when swallowed or applied heavily to broken skin or to infants. Applying a vapor rub under the nose of a small child is a recognized cause of airway irritation. Familiarity works against the whole group, because a product sold in a supermarket is rarely handled as a drug with a dose limit.
Also known as
Used in a sentence
A camphor containing rub was applied for muscle soreness.
Good to know
Camphor is absorbed rapidly and can cause a seizure within minutes of ingestion, sometimes as the first sign, and no antidote exists, which is why permitted concentrations in nonprescription products are capped.