The Food and Drug Administration (FDA) is a federal agency which regulates consumer food safety. It also approves and recalls drugs, medications, and medical devices, and conducts research, testing, and regulation of cosmetics and tobacco products. The FDA oversees the quality of food sold in the United States and requires labeling of ingredients.
New drugs must be approved by the FDA before they are advertised, prescribed or sold. Drug approvals require multiple steps including clinical trials that can take several years. Along with approving drugs, the FDA regulates drug advertising. Even though cosmetics don't require approval before sale, the FDA prohibits the use of certain chemicals in them. And, the agency also ensures the safety of vaccines, blood, and allergenic products, and has a specific approval process for each.
The FDA requires that some products have special labels about testing. Tobacco products also have FDA requirements regarding warning labels.