Camphor: Who needs it?

Camphor is a pleasant smelling cyclic ketone of the hydroaromatic terpene group. Its history dates to ancient Chinese medicine. Originally obtained by distillation of bark chips from the camphor tree Cinnamonum camphora, it is now produced synthetically. Camphor is an ingredient of a number of the over-the-counter remedies, particularly camphorated oil (20% camphor in cottonseed oil), spirits of camphor (10% camphor in alcohol), and many liniments, and is a component of paregoric (camphorated tincture of opium). Camphor is classified as a class IV chemical, i.e., very toxic substance, with a probable human lethal dose of 50 to 500 mg/kg. The ingestion of 2 gm generally produces dangerous effects in an adult, although 42 gm (1.5 oz) have been ingested with recovery, and 0.7 to 1.0 gm (1 tsp camphorated oil) has proven fatal in children. Although accidental oral ingestion is the most common route of intoxication, significant quantities can be absorbed percutaneously and via inhalation. Transplacental transfer may be toxic to the fetus. Camphorated oil, in particular, is the worst offender in accidental ingestions, because it is mistaken for a variety of over-the-counter products and is also accidentally ingested by toddlers. As long as camphor containing products continue to be marketed, pediatricians should warn parents of the dangers of camphor containing products in the home, especially camphorated oil.