Les drogues sont-elles bénéfiques pour la France ?

This article marks a break from the literature dedicated to assess the social cost of legal drugs (alcohol and tobacco) and illegal drugs because it also takes into account, in an Cost-Benefit analysis, the profits generated by drugs in order to measure their impact on the welfare in France in the 2000s. It turns out that all drugs have a negative impact on the welfare. Smoking decreases the welfare of ?14 billion, alcohol (?7 billions) and illegal drugs (?1 billion). The difference between the effects on the welfare of the alcohol and tobacco are due to several factors: revenue and consumer surplus are higher for alcohol than for tobacco. Public finances are very favourably affected by alcohol. The external cost is almost identical. Most of the negative consequences of illegal drug use are caused by so-called ?problematic drug users? most of which relates to cocaine and heroin. These drugs are little used; the negative effect on welfare is low. This research should be extended by attempting to assign precisely the negative impact of drugs for each specific patterns of consumption in order to calibrate public policies tailored to each consumer group (casual, regular, abusive). Classification JEL : H 51, D 61, D 62