This chapter analyzes instances of refusal to eat or drink due to the fear of poisoning and contamination amongst favela youth in Brazil. These particular occurrences of refusal shed light on refusal’s potency as a way of managing complex social entanglements and instrumental in asserting agency. Considering that interlocutors had come of age without many formal institutions present, they needed people. This artful skill had a flip side, for the proximity of people and the intensity of relationships could at times drain them and their emotional, social and economic resources. Discourses around poison, bad hearts and vampires thus emerge as aids towards the regulation of exchange involved in social relationships.