The study of ayahuasca represents a challenge to main­ stream culture through the phenomenon of new and novel forms of religious practice, exemplified by the ayahuasca churches of Brazil, which have lately spread to North America and Europe. As with the case of other plant hallucinogens employed as religious sacraments, in particular the use of peyote by the Native American Church, vital questions regarding freedom of religious practice will have to be addressed. To accurately determine ayahuasca's potential value as a medicine, it will ultimately be necessary to move beyond the boundaries of conventional treatment models and incorporate the lessons learned by past and dis­tant cultures.