The social and psychotherapeutic functions of healing rituals with ayahuasca among Amazonian groups are examined, and their healing effectiveness is explained in terms of Western scientific and sociopsychotherapeutic perspectives. The article includes an overview of the preparation and application of ayahuasca, the symbolic adaptations to the process of social change, the role of singing, the perceptive mode during the visionary state, and the structure of the visions. It is noted that the healing activities provide the entire community access to transcendental experiences, which clearly have integrative and cohesive social functions. Ethnopsychology provides important insights into the functions of archaic healing rituals, and can be used to illustrate the transcendental experiences and pathological use of drugs in modem societies.