Open street drug markets in the western industrialized world often create fear and outrage in the community. Many arguments posited by resident groups and local businesses against the introduction of harm reduction initiatives, such as fixed site needle and syringe programmes (NSP) and supervised injecting facilities (SIF), are based on the fear that such facilities will attract street drug markets. In this paper, we explore the fear produced in a city's encounter with street heroin use. Through linking a Deleuzian ontology to spatial practices associated with the street drug market, we provide a deeper understanding of the fear of public drug use. After examining how fear is produced, we then connect fear with the flows of capital in street drug markets and to the political and economic outcomes from such encounters.