Food and Drug Administration: An agency within the US Public Health Service that provides a number of health-related services. Abbreviated FDA. The FDA's services include inspecting food and food-processing facilities to ensure wholesomeness and safety; scrutinizing food and drugs for pets and farm animals; ensuring that cosmetics will not cause harm; monitoring the health of the nation's blood supply; ensuring that medicines, medical devices, and biologicals (such as insulin and vaccines) are safe and effective; and testing radiation-emitting products such as microwave ovens to protect the public. The FDA also oversees health and safety labeling of these products. All new prescription and over-the-counter drugs are subject to FDA approval. The FDA must determine that a new drug produces the benefits it's supposed to produce, without causing side effects that would outweigh the benefits. It does so by looking at the results of clinical trials done outside the FDA. When serious adverse effects from a medication are reported, the FDA has the power to force the manufacturer to make changes in the drug, change its safety labeling or marketing practices, or remove the medication from the market.