Public health refers to all organized measures (whether public or private) to prevent disease, promote health, and prolong life among the population as a whole.
Its activities aim to provide conditions in which people can be healthy and focus on entire populations, not on individual patients or diseases.
Thus, public health is concerned with the total system and not only the eradication of a particular disease.

The three main public health functions are:
- the assessment and monitoring of the health of communities and populations at risk to identify health problems and priorities;
- the formulation of public policies designed to solve identified local and national health problems and priorities; and
- to assure that all populations have access to appropriate and cost-effective care, including health promotion and disease prevention services.

WHO. Programmes and projects. Trade, foreign policy, diplomacy and health. Glossary of terms. 2010.