Based on earlier research on the French approach to drug use called risk reduction (réduction des risques) and an on-going investigation into a Brazilian approach called harm reduction (redução de danos), the article aims to understand the broader processes that permeate this public policy area in distinct social and political contexts, as well as the features that distinguish their various local manifestations. Pursuing this aim, I develop two analytical axes: a historiographical approach, interested in understanding the trajectory of risk reduction and harm reduction separately, especially the moral disputes and agreements relating to political openness to the policy and its institutionalization in both countries from the late 1980s to the early 2000s; and a contrastive approach, exploring the intersection of these sets of data, as a preliminary step in a broader investigation into risk/harm reduction.