Emergency medicine, also known as accident and emergency medicine, is the medical specialty concerned with the care of illnesses or injuries requiring immediate medical attention. As first-line providers, emergency physicians manage unscheduled patients of all ages with undifferentiated ailments of all types. They are primarily responsible for initiating resuscitation and stabilization and beginning investigations and interventions to diagnose and treat illnesses in the acute phase. Emergency physicians generally practice in hospital emergency departments, pre-hospital settings via emergency medical services, and intensive care units, but may also work in primary care settings such as urgent care clinics. They may subspecialize in fields like disaster medicine, medical toxicology, ultrasonography, critical care medicine, hyperbaric medicine, sports medicine, palliative care, or aerospace medicine.
                  
Different models for emergency medicine exist internationally. In countries following the Anglo-American model, emergency medicine was originally the domain of surgeons, general practitioners, and other generalist physicians, but in recent decades it has become recognised as a speciality in its own right with its own training programmes and academic posts, and the specialty is now a popular choice among medical students and newly qualified medical practitioners.By contrast, in countries following the Franco-German model, the speciality does not exist and emergency medical care is instead provided directly by anesthesiologists (for initial resuscitation), surgeons, specialists in internal medicine, or another speciality as appropriate. In developing countries, emergency medicine is still evolving and international emergency medicine programs offer hope of improving basic emergency care where resources are limited.