The public health definition is based on the concept of social welfare. Public health is a discipline that works to protect the health of a given population. The goal is for each individual to be physically and mentally healthy. To achieve this, it uses different tools: education in schools, promotion of healthy lifestyles through the media, and prevention campaigns of various diseases. The development of public health is carried out by the various governments of a population (state, country, city, etc.) responsible for correctly executing the various planned health programs. During this process, it is necessary to involve different sciences and disciplines: medicine, nursing, statistics, psychology, biology, sociology, etc. All this knowledge is integrated to promote good health in the population.

For health policies to be truly effective, governments must first study the needs of their populations. Based on that, health plans are developed to meet those needs. The most essential functions of public health are prevention, health promotion, and health restoration to become healthy again. A fundamental part of a successful public system is the excellent management of health resources, which must reach as many people as possible. The state must ensure that everyone has access to good health care. Unfortunately, different populations worldwide cannot achieve this ideal, as their respective health systems are collapsed.

The public health definition implies a multidisciplinary approach since different disciplines must be coordinated to achieve the goal of satisfactory population health. For a health care system to work well, the efforts of doctors are not enough. Knowledge of sociology, social psychology, economics, financial management, etc. is needed. Governments must articulate all this knowledge so that a system is complete and can satisfy the needs of a population. The development of public policy can determine essential aspects such as life expectancy, the effectiveness of vaccination campaigns, and the control of a pandemic, among several others.

Other fundamental aspects of a sound health system are the promotion of personal and collective hygiene, physical exercise, and care of the environment. Each individual has the responsibility to lead a healthy life, promote good habits, and educate the children in their family so that they grow up in a hygienic environment. Then those children become happy adults who care for and value their bodies. As can be seen, public health definition not only concerns a government but also the active participation of each citizen.