The modern concept of public health, the New Public Health, carries a great potential for healthy and therefore less aggressive societies. Its core disciplines are health promotion, environmental health, and health care management based on advanced epidemiological methodologies. The main principles of living together in healthy societies can be summarized as four ethical concepts of the New Public Health essential to violence reduction equity, participation, subsidiarity, and sustainability. The following issues are discussed as violence determinants: the process of urbanization; type of neighborhood and accommodation, and consequent stigmatization; level of education; employment status; socialization of the family; women's status; alcohol and drug consumption; availability of the firearms; religious, ethnic, and racial prejudices; and poverty. Development of the health systems has to contribute to peace, since aggression, violence, and warfare are among the greatest risks for health and the economic welfare. This contribution can be described as follows: 1) full and indiscriminate access to all necessary services, 2) monitoring of their quality, 3) providing special support to vulnerable groups, and 4) constant scientific and public accountability of the evaluation of the epidemiological outcome. Violence can also destroy solidarity and social cohesion of groups, such as family, team, neighborhood, or any other social organization. Durkheim coined the term anomie for a state in which social disruption of the community results in health risks for individuals. Health professionals can make a threefold contribution to peace by 1) analyzing the causal interrelationships of violence phenomena, 2) curbing the determinants of violence according to the professional standards, and 3) training professionals for this increasingly important task. Because tolerance is an essential part of an amended definition of health, monitoring of the early signs of public intolerance is important. The vital interplay between the informed public and efficient administration, however, can only exist in an open society. The link between democracy and health of the people, and between public health and economic welfare is real. The Public Health Collaboration in South Eastern Europe (PH-SEE) evolved just in time to reconnect and strengthen disrupted professional networks in the region as a prerequisite of effective public health action.