Medicine is a science that studies the causes, processes, and effects of disease. It is an interdisciplinary field that incorporates knowledge from many other sciences such as biology, chemistry and physics. Other important areas of study include pharmacology (the study of drugs), radiology (the study of radiation and its interaction with living things), endocrinology (the study of hormones), pathology (the scientific study of disease, including the morphologic changes caused by them) and physiology (the normal functioning of an organism).

Historically, much of medicine was both art and science. For example, stitching technique for sutures is an art learned through practice; however, the principles of cellular and molecular biology that underlie this skill are science. Similarly, ancient medical practices were often linked to religious and philosophical beliefs such as animism (the notion that inanimate objects have spirits), spiritualism or shamanism.

In modern times, most medicine is conducted within health care systems that are organized around legal, credentialing and financing frameworks established by governments or other agencies. Often these systems are designed to provide care for all or most members of a society regardless of their ability to pay. This is accomplished through a range of strategies such as preventive care, treatment and rehabilitation. Modern medicine is also characterized by an increasing emphasis on patient advocacy, informed consent and the ethical principle of respect for persons. Conflicts between these values and other social, cultural or personal beliefs may result in ethical dilemmas.