The level of global small arms violence is enormous and the scale of human suffering it causes is immense, although poorly counted. It causes at least hundreds of thousands of deaths and more than a million injuries each year, as well as permanent physical and psychological damage, destruction of families, lost productivity, and diversion of resources from basic health services. Research is required on three basic issues, as follows: health effects of weapons; the contributing factors and causes, including behavioral issues; and impacts of interventions and their cost-effectiveness. Policies and programs designed to reduce the human and social impacts of small arms should make use of public health knowledge and analysis of risk factors as a means of bringing increased focus and effectiveness to their objectives. At its international conference on small arms, gun violence, and injury, "Aiming for Prevention" in Helsinki in September 2001, International Physicians for the Prevention of Nuclear War called on health professionals as well as scientists, activists, humanitarian and development workers to contribute to an effective confrontation of the small arms pandemic.