This paper is a reflection on the ritual incorporation of ayahuasca, an Amazonian psychoactive ritual substance, by members of a Guarani Indian village on the Atlantic coast of the state of Santa Catarina, Brazil. Their shamanic leaders have adapted the use of this beverage into their ritual practices and recognize it as part of their culture and tradition. This process of appropriation is a result of the formation of a network that involves various actors, among them the Guarani Indians, members of Sacred Fire of Itzachilatlan, followers of the Brazilian ayahuasca religion Santo Daime, and a health team employed to provide primary attention to Indian communities. Based on this case study, we demonstrate that shamanisms today emerge out of specific political and historic contexts. If the concept of shamanism is useful as an analytical paradigm, it must be thought of as a dialogical category constructed through interaction between actors with diverse origins, discourses, and interests.