The Department of Health and Human Services (HHS) is the United States government's principal agency for protecting the health of all Americans and providing essential human services, especially for those who are least able to help themselves. 

Agencies of HHS conduct health and social science research, work to prevent disease outbreaks, assure food and drug safety, and provide health insurance.

In addition to administering Medicare and Medicaid, which together provide health insurance to one in four Americans, HHS also oversees the National Institutes of Health, the Food and Drug Administration, and the Centers for Disease Control.

The Secretary of Health and Human Services oversees a budget of approximately $700 billion and approximately 65,000 employees. The Department's programs are administered by 11 operating divisions, including 8 agencies in the U.S. Public Health Service and 3 human services agencies.

https://www.hhs.gov/