Background: Clinical guidelines are increasingly used in patient management but few clinicians are familiar with their origin or appropriate application.Methods: A Medline search using the terms 'clinical guidelines' and 'practice guidelines' was conducted. Additional references were sourced by manual searching from the bibliographies of articles located.Results and conclusion: Clinical guidelines originated in the USA in the early 1980s, initially as a cost containment exercise. Significant improvements in the process and outcomes of care have been demonstrated following their introduction, although the extent of improvement varies considerably. The principles for the development of guidelines are well established but many published guidelines fall short of these basic quality criteria. Guidelines are only one aspect of improving quality and should be used within a wider framework of promoting clinical effectiveness. Understanding their limitations as well as their potential benefits should enable clinicians to have a clearer view of their place in everyday practice.