In front of the awkwardness of the Western people in relation with the modified states of consciousness, ancestral medicines answer with a very sophisticated knowledge. In that case, the non-ordinary states of consciousness are not damageable when controlled and give the opportunity to face the recent development of addictions. From his experience in the High Peruvian Amazonian forest, the author describes the therapeutic resources of a wise use of medicinal plants including the psychoactive ones such as the famous ayahuasca beverage. The elaboration of a therapeutic system, within an institutional framework, which combines traditional practices and modern psychotherapy, gives efficient and encouraging results. It invites us to enlarge the conventional approach towards the universal notion of initiation. This aspect, forgotten in the Western modern context, seems to be the purpose of the spiritual quest required by drug addicts.