Cannabinoids are several structural classes of compounds found primarily in the Cannabis plant or as synthetic compounds. The most notable cannabinoid is the Phyto cannabinoid tetrahydrocannabinol (THC) (delta-9-THC), the primary psychoactive compound in cannabis.[3][4] Cannabidiol (CBD) is a major constituent of temperate cannabis plants and a minor constituent in tropical varieties. At least distinct phytocannabinoids have been isolated from cannabis, although only four (THCA, CBDA, CBCA, and their common precursor CBGA) have a confirmed biogenetic origin.[6] Phytocannabinoids are also found in other plants, such as rhododendron, licorice, and liverwort.

Phyto cannabinoids are multi-ring phenolic compounds structurally related to THC,[8] while endocannabinoids are fatty acid derivatives. Nonclassical synthetic cannabinoids (cannabimimetic) include aminoalkylindoles, 1,5-diarylpyrazoles, quinolines, and aryl sulfonamides, as well as eicosanoids related to endocannabinoids.[