Andrew Booth offers a comprehensive look into national and international guidelines surrounding the diagnosis and management of asthma National and international guidelines provide evidence-based advice on the diagnosis and management of asthma. There are now three potential asthma guidelines to follow, each taking its own unique, and sometimes conflicting direction, creating a total of over 700 pages of high-quality evidence. A puzzle is thus presented to the busy health professional: which guideline do I follow? This article compares and contrasts two national and one international asthma guideline, focusing particularly on diagnosis and pharmacological management. Mortality from asthma is increasing in the UK, making the need for a conjoined guideline more urgent than ever.