[Epidemiology and public policies].

The present essay deals with the relation between epidemiology and public policies, highlighting the epidemiology position in the public health field, analyzing the impact of public policies over epidemiological profile and contributions from epidemiology to the lay down, implementation and evaluation of public health policies. In the first title, the essay debates the links between the epidemiology and public health field, the social determinants and political action framework proposed by the WHO's Commission on Social Determinants of Health, and different approaches of health policies. In the second title the essay analyses the reduction of child stunting in Brazil as an example of public policies that impact epidemiological profile. The third title presents three strategic topics for the application of public health policies: reduction of social inequalities in health, health promotion and regulation of products and services that have impact over health. The fourth title discusses the possibilities and difficulties to combine the epidemiological knowledge in the lay down, implementation and evaluation of public policies and, finally, material examples of such relation between epidemiology and public policies are presented.