In France, patterns of use of various psychoactive substances (both legal and illegal), as well as recent trends, have been tracked for the past decade through a series of representative surveys of the general population. This monitoring system relies in particular on the Health Barometers coordinated by INPES since the early 1990s, as well as on the OFDT’s data collections on young people beginning in 2000. One of the key roles of these surveys is to provide contextual data, such as the proportions of regular users or experimental users. The data from the 2005 Health Barometer presented in this issue of Trends provide an update on the levels of use of various legal and illicit substances; the analysis by substance offers an opportunity to document, for the first time, a number of previously unaddressed issues related to alcohol and cannabis.