After addressing the place of therapeutic use of hallucinogens in traditional societies and their role in initiative and shamanic practices, the second part of this file addresses the issue of therapeutic use for cannabis, LSD, ketamine, MDMA-Ecstasy, mescaline, ibogain, GHB. For each of them history shows an important experimentation and practice of therapeutic use, which was banned in Western societies in the second place with the emergence of new patterns of consumption from the 1960s. For this article committed a hypothesis should be pursued in the cultural, social and political approach to the drug problem: “is there not a fundamental error in demonizing hallucinogens (and cannabis) and preventing socially integrated use, a source of integrative hetero-control, especially therapeutic use and use festive?”. Particularly topical debate regarding the therapeutic use of these substances in palliative or pain care. A comprehensive review of the literature and work in progress is carried out. It shows the resumption of therapeutic trials in different countries, for example: Raphael Mechoulam for cannabis (Israel), MAPS and Hefter Research Institute for LSD (USA), Krupitsky for ketamine (Russia), Grob for MDMA (USA), Grob, Lotsof (USA) and Mabit (Peru) for ibogaine. This article presents 145 bibliographic references.