Borneol is a bicyclic organic compound and a terpene. The hydroxyl group in this compound is placed in an endo position. Isoborneol is its exo isomer.

Borneol refers both to a specific chemical compound and to a mixture of similar compounds (of which borneol is one) in a resinous crude material obtained from certain herbs. The chemical constituent borneol is one of the active ingredients of artemisia, which contains other aromatic compounds of similar structure and medicinal function. Borneol is used in traditional Chinese medicine as moxa. An early description is found in the Bencao Gangmu. Both borneol (as a crude resin) and artemisia are utilized internally and externally in the practice of Chinese medicine. Moxa is shredded artemisia that is burned on or near the body to produce local heating, as well as to generate an additional influence from the moxa material itself, perhaps imparting borneol and other active constituents to the body. In this article, the properties, uses, and interrelations of borneol, artemisia, and moxa are explored.

Borneol is easily oxidized to the ketone yielding camphor. One historical name for borneol is Borneo camphor which explains the name. Borneol can be synthesized by reduction of camphor by the Meerwein-Ponndorf-Verley Reduction. The same reduction but then fast and irreversible with sodium borohydride gives isoborneol as the kinetically controlled reaction product.

The typical form of borneol is in thin, semi-opaque, whitish angular pieces or crystals, and this appearance is the reason for its current Chinese name (bing = ice, pian = slice). A detailed description of this substance appeared in the Bencao Gangmu (1596 A.D.), where it was not called bingpian, but rather was called ai (same Chinese character as used for aiye, artemisia). The association with aiye (Artemisia argyii) is not coincidental: the active constituents of aiye include borneol, camphor, and cineole, which are also the main components of natural bingpian. Blumea, the local Chinese source of bingpian, is in the same plant family as artemisia (Compositae); it is not uncommon for plants of the same family to yield similar chemical ingredients. Blumea is called ainaxiang (fragrant herb that looks like artemisia).

Borneol is a component of many essential oils, and it is a natural insect repellent. Today borneol is classified as an agent for opening blocked orifices, and is described as pungent, bitter, and slightly cold . It is indicated for severe obstruction of the orifices (that may cause coma or convulsive diseases), for heat syndromes, and for pain. Although not often mentioned as useful for this purpose, borneol is a common addition to treatments for lung diseases in modern clinical practice. It is also applied topically (usually with other substances) for a wide range of conditions, mainly for swelling in the throat, mouth sores, ear infections, cervical erosion, psoriasis, boils, pain, and eye diseases.