Ian Roberts, lecturer in Clinical Trials Unit, LSHTM, gives the 2013 Cochrane lecture on Trials in Emergency Care. He discusses the need for clinical trials in emergency situations and explains how such trials can and should be conducted. Clinical trials are essential for improving the safety and effectiveness of emergency care. Many such trials seek to evaluate the effects of time-critical treatments for life threatening conditions, such as traumatic brain injury, severe haemorrhage or acute respiratory distress. The need for urgent treatment, often excludes the possibility of obtaining informed consent. Although these situations are an established exception to the general rule of prior informed consent, ethics committees and regulators often insist on various unhelpful rituals that delay the initiation of a trial treatment with the effect that the treatment effect may be reduced or obscured. This presentation discusses the need for clinical trials in emergency situations and explains how such trials can and should be conducted.