Clinical practice guidelines: what they are, why we need them and how they should be developed through rigorous evaluation.

The number of available clinical practice guidelines has grown enormously in the recent years, therefore requiring a correct approach and use of them. We present a revision of what guidelines are and serve, how to correctly develop and find them, and how to develop and evaluate them through rigorous scientific methods. Limits and benefits of guidelines are also discussed. An overview about the use of paediatrics' guidelines is finally reported.