An acute medical unit (AMU) is a short-stay department in some British, Australian and New Zealand hospitals that may be linked to the emergency department, but functions as a separate department. [1] The AMU acts as a gateway between a patient's general practitioner, the emergency department, and the wards of the hospital. The AMU helps the emergency department produce a healthy turnaround for patients, helping with the four-hour waiting rule in the United Kingdom. An AMU is usually made up of several bays and has a small number of side-rooms and treatment rooms. They are fully equipped with emergency medical treatment facilities including defibrillators and resuscitation equipment.