Mescaline (3,4,5-trimethoxyphenethylamine) is a hallucinogenic alkaloid of the phenethylamine class.
It occurs naturally in the peyote cactus (Lophophora williamsii), the San Pedro cactus (Echinopsis pachanoi) and the Peruvian Torch cactus (Echinopsis peruviana), and in a number of other members of the Cactaceae. It is also found in small amounts in certain members of the Fabaceae (bean family), including Acacia berlandieri. Mescaline was first isolated and identified in 1897 by the German Arthur Heffter and first synthesized in 1919 by Ernst Späth.