The practitioner is very frequently confronted by emergencies in drug-addicted patients also having psychiatric symptomatology. In this article the authors will address emergencies related to alcohol (notably intoxication, pre-DTs and the encephalopathies); emergencies related to cannabis (notably intoxication, psychotic states and panic attacks); and emergencies related to other psycho-active substances (overdoses, drug-withdrawal, psychiatric complications related to cocaine or amphetamines). In the domain of drug addiction, as in psychiatry, the practitioner must give as much importance to the organisation of the long-term healthcare plan for the drug addict, ulterior to the management of the immediate emergency. For example, whereas 90% of subjects presenting to the emergency department for acute alcoholic intoxication have a pathological consumption of alcohol (abuse or dependance), management of the alcoholism is proposed in only 2% of them.