[Opposable medical references in perspective]

We present the French medical references under their double characteristics of 'conventional' and therapeutic instruments. On one hand, they are conventional because they illustrate a phase of the relations between medical organisations and the health insurance fund (embodied in 'National Conventions'), of which they clearly illustrate the evolution towards the control of medical care. On the other hand, the last National Convention stipulates that medical references 'define medically unnecessary care and prescriptions', thereby being a prescription guide or guideline, all the more so as they are compulsory. We describe the evolution of the Conventions, and discuss the appropriateness of the references as therapeutic guidelines.