“The mescalbean among the North American Natives” – With the name “mescalbean cult” or “mescalism”, a group of ritual practices of the North American Planes Natives are named, during which a vegetal psychoactive source was employed. The human relationship with this visionary source originates starting from the most remote antiquity, and lasted until the end of the XIX century of our era. In the present study the historical, ethnographical, archaeological, and mythological aspects of these rites are reviewed, bringing clarifications on the problem of the relationship of mescalism with peyotism, and on some terminological and ethnobotanical confusions which dragged in the studies for several decades. Lastly, some ethological aspects concerning the animal relationship with the mescalbean are analyzed, and which could clarify the origins of the human relationship with this intoxicant source.