The author presents the setting and conditions for the “production” of hallucinations during traditional therapy involving the use of the Ayahuasca, liana which has psychotropic effects. The presentation is based on the author's self-experimentation carried out with curanderos of the peruvians upper amazon region. He attemps to find some constants which would permit characterization of the consecutive hallucinations caused by ingesting Ayahuasca. He then proposes meditation on the vision achieved through these practices. He defines the criteria which, according to him, make these modifications of the conscious state worthy of interest, particularly from the therapeutic point of view.