[Collective of users in the fields of AIDS and drug addiction].

The extent of mobilization caused by the epidemy of AIDS was underlined many times. Because of a logic of selective dissemination, infection by HIV not only started action of patients and their close relations, but also that of the two most affected social groups : homosexual men and drug users. Existing since almost a century, the collectives of patients have shown various configurations, from consensual groups which developped in the thirties to protestor groups emerging within the seventies. We show here how both in AIDS and drug addiction, the collectives of users multiplied through differentiated public identification choices. In the fight against AIDS, all the forms of mobilization coexist. Concerning drugs usage, actions are less diversified and divide in two main categories: groups of interest and self-help groups.