[Crack usage circuits in the downtown area of the city of São Paulo (SP, Brazil)].

Although drug usage has been prevalent since the dawn of humankind, drug abuse has currently escalated alarmingly and can be characterized as a public health problem. The spread of "crack," a drug derived from cocaine paste, is worsening the situation by aggravating the social damages and harming the health of users. An ethnographic study was conducted in downtown São Paulo, SP (Brazil) in locations where crack is sold and used in order to establish the impact of the spread of this drug in the daily life of users. A field diary was used to record the observations and informal dialogues with the people who circulate in the location under scrutiny. The results of this study show the circuits covered by the users, their dynamics and the complex relationships with other social players, based on permanent tension, involving the practice of violence in which the users are both victims and perpetrators. The study also suggests the importance of other factors such as the history of the region in question, the public policies, economic questions and the lack of social investments and public health. It is suggested that the advanced degree of degradation of the region researched is not only the result of the people and activities practiced in the area, but also mainly of the urban process that led to such a social scenario.