Public health is the science dealing with prevention of a disease that is a threat to the overall health of a community , as well as with prolonging life and promoting health . The aims are achieved through the organized efforts and informed choices of society , public and private organizations , communities and individuals . Public health is `` the science and art of preventing disease , prolonging life and promoting health through the organized efforts and informed choices of society , organizations , public and private , communities and individuals '' ( 1920 , C.E.A. Winslow ) .