A physician (American English), medical practitioner (Commonwealth English), or a medical doctor is a health professional who practices medicine, which is concerned with promoting, maintaining, or restoring health through the examination, diagnosis, and treatment of disease, injury, and other physical and mental impairments. Other responsibilities include: giving advice on diet, hygiene, and preventative care, examining patients, prescribing medications, ordering, giving, and interpreting diagnostic tests, along with taking and keeping medical histories.

There are generally two types of physicians: medical doctors (MD) and doctors of osteopathic medicine (DO). They use the same methods of treatment, including drugs and surgery, but DOs also focus on the body’s musculoskeletal system, preventative medicine, and holistic patient care.