This chapter explores the historical process through which the use of ayahuasca in Brazil became recognized as a religious and cultural tradition. The chapter highlights how anthropological discourse played a critical role in redefining ayahuasca use from a stigmatized practice associated with drugs to an integral part of Brazil’s religious and cultural landscape. Drawing on historical documents, government reports, media archives, and interviews, the analysis traces the interplay between state policies, legal frameworks, and academic classifications that ultimately enabled the formal recognition of ayahuasca use as a religious practice, distinguishing it from illicit substances. By focusing on the processes of regulation and legitimization, the chapter sheds light on the broader implications of defining religious and cultural heritage within the framework of public policy.