Armed conflict (war) has profound and extensive impacts on public health. It causes morbidity and mortality directly, mainly from explosive weapons, and indirectly, due to destruction of health-supporting infrastructure and forced displacement of populations. Armed conflict damages the environment and the preparations for war divert human and financial resources away from health care, public health, education and other social services to support the community. Public health professionals play important roles in documenting the health consequences of war, raising awareness of these consequences and advocating for the prevention of war and the promotion of peace.