Clinical guidelines are not implemented in a simple linear way, their integration in clinical practice is an evolving process influenced by the doctor, the patient and society. Methodologically, it is not easy to evaluate definitively the impact of guidelines. The overall appraisal yields a pessimistic conclusion: in most cases, guidelines do not translate well enough into action (effect on physician behaviour) and are believed to express motivation rather than optimum care. To avoid an academic mirage, recommendations must be disseminated in ways that provide incentives for such action. Those to whom guidelines are directed must be remarkably receptive to, and already prepared to act on the message. There are some indications that the most successful strategy to change the behaviour of clinicians and general practitioners operates at a more local level, and with more careful targeting, than is feasible with a national or regional consensus exercise. In addition, a more forceful action plan and multi-pronged approach (e.g. including continuous medical education) is required.