In the present bachelor thesis, the effects of public health preventive measures, in the form of streetwork be examined more closely with drug addicts. At the beginning, the phenomenon addiction is visually observed. Subsequently, it is determined what defines a drug scene, based on the work of “suchthilfe wien”. In the main part, the most diverse forms of health prevention of drug addicts as harm reduction or substitution are described. Following explains what comorbidities on somatic, psychological and social level can occur if no preventive health care was available and / or has taken place. The method streetwork as health prevention for drug addicts is the central theme in this work. Chapter 7 explains the question: does street work in the form of relationship work, safer use counseling, emergency assistance and process-oriented care can effect health prevention.