From its origins as six western European countries coming together to reduce trade barriers, the European Union (EU) has expanded, both geographically and in the scope of its actions, to become an important supranational body whose policies affect almost all aspects of the lives of its citizens. This influence extends to health and health services. The EU's formal responsibilities in health and health services are limited in scope, but, it has substantial indirect influence on them. In this paper, we describe the institutions of the EU, its legislative process, and the nature of European law as it affects free movement of the goods, people, and services that affect health or are necessary to deliver health care. We show how the influence of the EU goes far beyond the activities that are most visible to health professionals, such as research funding and public health programmes, and involves an extensive body of legislation that affects almost every aspect of health and health care.