Medicine is the branch of health science and the sector of public life concerned with maintaining or restoring human health through the study, diagnosis and treatment of disease and injury. It is both an area of knowledge — a science of body systems, their diseases and treatment — and the applied practice — an art or craft — of that knowledge. However, medicine often refers more specifically to matters dealt with by physicians and surgeons.
Medicine is both an area of knowledge (a science), and the application of that knowledge (by the medical profession and other health professionals such as nurses). The various specialized branches of the science of medicine correspond to the equally specialized medical professions dealing with particular organs or diseases. The science of medicine is the knowledge of body systems and diseases, while the profession of medicine refers to the social structure of the group of people formally trained to apply that knowledge to treat disease.
Medicine comprises various specialized sub-branches, such as cardiology, pulmonology, neurology, or other fields such as sports medicine, research or public health.
"Medicine" is also often used amongst medical professionals as shorthand for internal medicine. Veterinary medicine is the practice of health care in animal species other than human beings.