Medical is the branch of health care that deals with diagnosis, treatment and prevention of disease. The field is multidisciplinary, incorporating research from biology (including biochemistry and molecular medicine), physics (including medical imaging and radiology) and physiology, as well as mathematics, computer science, statistics, engineering, chemistry, philosophy, ethics, social sciences and history.

The modern system of medicine traces its roots to the ancient Greek physician Hippocrates, who established the Hippocratic Oath for physicians and laid the foundation for a rational approach to illness based on observation, reason and experimentation. Modern medicine encompasses a wide range of specialties, many of which require additional training after medical school, as well as sub-specialty fellowships.

Medicine is a regulated profession in most countries, meaning that doctors must undergo extensive education and training before being allowed to practice, usually by passing national examinations. This ensures that doctors have been exposed to a broad base of knowledge and are competent to practise medicine, while also limiting the ability of unscrupulous people to claim to be medical practitioners and thus exploit vulnerable patients.

Psychiatry is the medical specialty that studies and treats mental disorders, including psychoses and personality disorders. Pediatrics (American English) or paediatrics is the branch of medicine dealing with children’s health and diseases from infancy through adolescence. It includes neonatology. Surgery is a broad field, with many different subspecialties. Pathology is the scientific discipline that studies bodily disease, with subspecialties in cancer, infectious disease and hematology. Medicine is a large and diverse field with many branches, and a wide range of related careers such as pharmacology, clinical research, epidemiology, public health and preventive medicine.

Prehistoric medicine incorporated plant (herbalism), animal and mineral materials in rituals to cure or prevent disease, often involving spiritual systems such as animism, spiritualism, shamanism and divination. These were often based on the belief that inanimate objects had spirits, or that illness was caused by interference with these spirits.

Medical anthropology is the study of the way in which culture and society are organized around and impacted by medical science and healthcare. The history of medicine is an important part of the history of human civilizations, as recorded in the Egyptian papyri, Chinese medical texts, Ayurvedic and classical Indian medicine, and the European medical schools founded during the Renaissance such as those at Florence, Pisa and Siena.