In this chapter I describe a tobacco diet that I participate in in November 2013, which takes place in the Peruvian city of Iquitos. This description is a microethnography (cf. Erickson, 1971, cit. in Streeck and Mehus, 2004:382) based on intensive data collection over a short period of time and in a delimited geographical space, in which the production and interpretation of data shares the same ontological postulates — premise of the existence of spirits, forces or energies, epistemological — first ontological turn, and decoloniality of knowledge and being — and methodological — observation, participation and radical participation — and techniques — daily conversations with participants, an hour and a half interview with the shamans, and audio recording of two works — which have been followed in the study of ayahuasca ceremonies. The aim of including this microethnography in this work is to be used as an extended case to carry out, in Chapter 7, a joint analysis of ayahuasca ceremonies and tobacco diet, to try to obtain a better understanding of what shaman does during work with ayahuasca.