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Camphor is a bicyclic monoterpene ketone that is widely found in various plants, notably Cinnamomum camphora. It has medicinal uses, particularly as a topical skin antipruritic and anti-infective agent. However, when ingested, camphor can be toxic with rapid onset of effects, with camphorated oil often being responsible for this toxicity. As a result, the FDA has regulated that camphorated oil cannot be marketed in the United States, and no product should contain more than 11% concentration of camphor. This substance is included in the list of drug products that have been withdrawn or removed from the market due to safety or effectiveness concerns, though camphor is still found in various nonprescription medications at lower concentrations. Camphor is a waxy, colorless solid with a distinct strong aroma, classified as a terpenoid and a cyclic ketone. It is naturally found in the wood of the camphor laurel (Cinnamomum camphora), a large evergreen tree native to East Asia, and the kapur tree (Dryobalanops sp.), a tall timber tree from Southeast Asia. Other sources include trees in the laurel family like Ocotea usambarensis, rosemary leaves (Rosmarinus officinalis) which contain small amounts of camphor, and camphorweed (Heterotheca) with a higher concentration. A significant source in Asia is camphor basil. Additionally, camphor can be synthetically produced from oil of turpentine. Camphor is a chiral compound, existing in two enantiomeric forms. The structure on the left represents the naturally occurring (+)-camphor ((1R,4R)-bornan-2-one), while the right structure is its mirror image, (−)-camphor ((1S,4S)-bornan-2-one). While camphor has limited uses today, it holds historical significance as a compound easily purified from natural sources.

Chemical and Physical Properties

Source: PubChem