The purpose of this study is to discuss how the Sanumá indigenous people, a subgroup of the Yanomami linguistic family, located in northern Roraima State, Brazil, interacts with and relates to the public policy for indigenous people's health. Missionaries and Brazilian government and non-governmental organization employees are the agents with whom the Sanumá had to deal during the implementation of a healthcare policy. The ethnography of this interrelationship, permeated by moments of epidemic outbreaks, clashes, and attempts at collaboration, raises questions on the implementation of health services in indigenous territories.