aromatic gum resin containing a volatile oil that was valued in ancient times in worship and as a medicine and is still an important incense resin. Frankincense is obtained from trees of the genus Boswellia (family Burseraceae), and particularly from the varieties B. frereana, B. bhaw-dajiana, and B. carteri, which are found in Somalia, the Hadhramaut region of Yemen, and Oman. Incisions are made in the trunks of the trees, and the frankincense exudes as a milklike juice that hardens on exposure to air.

Frankincense was used by the ancient Egyptians in their religious rites. It constituted part of the Jewish incense of the sanctuary and is frequently mentioned in the Pentateuch. Pliny the Elder described the characteristics of good-quality frankincense and mentioned it as an antidote to hemlock poisoning. The Iranian physician Avicenna recommended it for a wide range of bodily ailments. In China and elsewhere in the East, it was used as both an internal and an external remedy, but, according to modern Western medical theory, it has no special value. Frankincense is used in incense and fumigants and as a fixative in perfumes.

The hardened gum resin, gum thus, from which spirits of turpentine is produced, is sometimes called common, or American, frankincense.