This paper begins by exploring central dimensions to the practice of ayahuasca shamanism in the Amazon concentrating on the question of cosmological metamorphosis and reports of shamans becoming jaguars, plants, birds or various other beings of the cosmos. Practices of healing and notions of Amerindian health take precedence in this opening analysis. This is followed by an introduction to the practice of ayahuasca healing in Australian society based on fieldwork undertaken in 2011 and 2012. Preliminary contrasts between Amazonian and Australian traditions are explored and the paper finishes with some reflections on the nature of cosmological metamorphosis and synaesthesia. The paper does not attempt to create a kind of grand or total comparison between the use of ayahuasca in Amazonia and Australia—I am doubtful whether such a thing is even possible—but it aims at elucidating some of the radically different worlds and ways in which ayahuasca is involved in practices of healing.