This chapter examines the regulation of medicines in the United States. The US scheme for achieving the primary goals of medical product regulation is largely federal, governed by the Food, Drug, and Cosmetic Act and two provisions of the Public Health Service Act and administered by the US Food and Drug Administration (FDA), a federal executive branch agency within the US Department of Health and Human Services. Federal law generally requires research before a medical product enters the market, FDA authorization before market launch affirming that there is sufficient evidence of the product's safety and effectiveness, and continued monitoring and regulation after launch. These requirements and how they are implemented, however, reflect values and goals that, in some circumstances, can be in tension. The chapter then considers how the regulatory scheme for medicines seeks to reconcile these sometimes competing values and goals. It starts by describing what constitutes a medicine subject to FDA regulation and then explains how medicines reach the market, how the FDA and manufacturers assess and manage risks, and the incentives for innovation and rules for competition. The chapter also looks at innovative medical technologies that challenge the traditional US regulatory scheme, using those examples to explore the future of medicines regulation.