Abstract : The purpose of this research is to outline the trajectory of harmreduction s policy in the city of Florianópolis, capital of Santa Catarinastate, based on the narratives and perspectives of the workers involvedin its implementation. Harm reduction is considered a policy that aim toreduce the harms associated with the use of psychoactive substances inpeople unable or unwilling to stop, and does not have as its mottoabstinence, either as a necessary mean or goal. It was developedthrough Syringe Exchange Programs and thus reaches Brazil, even inFlorianópolis, fomented from the STD / AIDS State Program, still in the1980s, in response of the high rates of HIV transmission betweeninjecting drug users, who became infected through syringe sharingpractices and unprotected sex. In 1993, the First National Seminar onHIV / AIDS Prevention among IDUs was held, considered an importantmilestone, from which injecting drug users are seen and theFlorianópolis Harm Reduction Program is promoted. Its developmentsare traced in this dissertation until its apparent dissolution in thebeginning of the decade of 2010. Also the notions and the perspectivesof the participants of the research on harm reduction, psychoactivesubstances and related subjects are approached.