Alpha-terpineol, also denoted as α-terpineol, is the most common of five closely related isomers, or sibling terpenes, within the terpineol family (the other members being beta-, gamma-, delta-, and 4-terpineol). It conveys a decidedly lilac aroma featuring heavy tones of pine.

This compound is produced by cannabis and more than 150 other plant species, including eucalyptus, freesia, lemon peel oil, lime blossoms, marjoram, narcissus, oregano, pine, and rosemary. It is found commonly in cultivars of cannabis that also produce relatively rich amounts of pinene.

Alpha-terpineol has shown distinct antianxiety efficacy and may contribute to the sedative-like “couchlock” effect of some potent cannabis strains. The medicinal efficacy of this terpene is among the most diverse produced by the cannabis plant and includes antibiotic, anti-inflammatory, antimalarial, antimicrobial, antioxidant, and antitumor benefits.