Many
cacti are known to be
psychoactive, containing
phenethylamine alkaloids such as
mescaline However, the two main ritualistic (folkloric) genera are
Echinopsis, of which the most psychoactive species is the
San Pedro cactus (
Echinopsis pachanoi, syn.
Trichocereus pachanoi), and
Lophophora, with
peyote (
Lophophora williamsii) being the most psychoactive species. Several other species pertaining to other genera are also psychoactive, though not always used with a ritualistic intent.