public health

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The science and practice of protecting and improving the health of a community, as by preventive medicine, health education, control of communicable diseases, application of sanitary measures, and monitoring of environmental hazards.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun medicine The science and practice of community hygiene; includes preventive medicine, health education, sanitation and environmental safety.