Department of Health and Human Services

HHS is the largest federal department by budget, responsible for protecting the health of all Americans. Its two biggest programs — Medicare (health coverage for 67 million seniors and people with disabilities) and Medicaid (health coverage for 90 million low-income Americans) — together account for roughly 25% of all federal spending. HHS also oversees the FDA, CDC, NIH medical research, and the Administration for Children and Families, which funds Head Start, foster care, and child support enforcement.