The British Thoracic Society consensus guidelines on the management of acute severe asthma1 are integral to Emergency Department management. If evidence-based medicine is to remain an important part of modern medical practice, all guidelines require regular review. The recent Cochrane systematic review of intravenous magnesium sulphate has demonstrated a clear role for this as a second line therapy which is both safe and easy to use.2 Another Cochrane review, however, has thrown clear doubt on a continuing role for intravenous aminophylline as a second line therapy due to lack of evidence of efficacy and a high rate of adverse reactions.3 The role of subcutaneous adrenaline in unresponsive cases is more anecdotal but it is certainly widely used and has been recommended for such situations in the consensus document produced by the Canadian Thoracic Society/Canadian Association of Emergency Physicians.4 The role of ketamine as the induction agent of choice, should rapid sequence intubation prove necessary, and the possible use of inhaled low dose anaesthetics as a rescue procedure also need to be addressed. We would urge the early review and update of current guidelines and the production of new standards for management of acute severe asthma in the Emergency Department.