This article provides an anthropological analysis of the introduction of medically prescribed heroin as part of official substance abuse treatment. While anthropological inquiries of substance abuse treatment have mainly focused on providing the users perspectives on the (ab)use or unraveling the conflicts and negotiations between users and staff, the present article argues for the merits of paying attention to the spatial dimensions of substance abuse treatment. Focusing on the spatial and material ramification of the treatment can shed a nuanced light on the still vulnerable process of altering the heroin from drug to medicine, and thereby on the attempts to settle heroin in a new practical and semantic landscape. The heroin is anchored in some powerful discourses of crime, death, and pleasure, and the analysis shows how these discourses (re-)appear in the spatial textures of the clinic, contesting the attempts to medicalize the heroin. Further, the article argues that even though the treatment aims at a marginalization of the heroin in the life of the clients, the spatial arrangements and the practices within them simultaneously enforces a centralization of the heroin, making the space for treatment highly ambivalent.