As soon as he prescibes medicine to an athlete, any physician is confrounted if he wants or not, and if he is aware of it or not, with the numerous and often complex rules treating with the universal fight against doping. In case of an involountary mistakee or not, the doctor can be involved in very unpleasant situations over different regulations. As ignorance is no valid defense form, it seems obvious that it is very imporant that each practitionner is informed the better possible about these legal aspects. This is the objective of the following presentation.