Even if there are few scientific data about preoperative management of drug addict patients, a careful anesthesiology evaluation facilitates the prevention of interactions between drugs and anaesthetics and avoids intraoperative and postoperative complications. Moreover it is important to earn the confidence of patient in order to know the abuse substances consumed and the frequency of consumption. This knowledge is necessary to the anaesthetist in order to manage possible withdrawal syndromes or overdose, which are the two greatest dangers for a drug addict patient during the hospital stay.