Emergency medicine (EM) is a global discipline that provides secondary disease prevention and is also a tool for primary prevention. It is a horizontally integrated system of emergency care consisting of access to EM care; provision of EM care in the community and during transportation of patients; and provision of care at the receiving facility or hospital emergency department. EM can offer many tools to improve public health. These tools include primary disease prevention; interventions for addressing substance abuse and interpersonal violence; education about safety practices; epidemiological surveillance; enrolment of patients in clinical research trials focusing on acute interventions; education and clinical training of health-care providers; and participation in local and regional responses to natural and man-made disasters. Public health advocates and health policy-makers can benefit from the opportunities of EM and can help overcome its challenges. Advocating the establishment and recognition of the specialty of EM worldwide can result in benefits for health-care education, help in incorporating the full scope of EM care into the system of public health, and expand the capabilities of EM for primary and secondary prevention for the benefit of the health of the public