Osteopathic medicine is "a whole system of medical care with a philosophy that combines the needs of the patient with modern practice of medicine, surgery and obstetrics. The importance is on the interrelationship between structure and function, and has an approval of the body's ability to heal itself." Outside the United States, "osteopathic medicine" is frequently used interchangeably with "osteopathy". Doctors of Osteopathic Medicine, or D.O.s, are skilled to apply the philosophy of treating the whole person to the avoidance, diagnosis and action of illness, disease and injury using conservative medical practice such as drugs and surgery, along with physical therapy (Osteopathic Manipulative Medicine or OMM).

As with Doctors of Medicine (M.D.s), D.O.s educated in the United States are completely licensed physicians and surgeons who apply the full scope of medicine. Currently, there are 27 qualified osteopathic medical schools in the United States and 125 accredited U.S. allopathic medical schools.

D.O. and M.D.-granting U.S. medical schools have related curricula. Usually, the first two years are classroom-based, even as the third and fourth years consist of clinical rotations through the main specialties of medicine. Upon graduation, both D.O. and M.D. physicians may opt to follow residency training programs. Depending on state licensing laws, osteopathic medical physicians may also be necessary to complete a one-year rotating internship at a hospital accepted by the AOA - the American Osteopathic Association.

Osteopathic medical physicians also have the chance to pursue allopathic residency programs; however, the converse is not at present permitted. Within the U.S., osteopathic medical physicians perform in all medical specialties including, but not incomplete to, interior medicine, emergency medicine, dermatology, surgery, and radiology. There is no distinction in compensation between allopathic and osteopathic physicians. Physician salaries do differ between the various medical specialties. Osteopathic medical physicians educated in countries exterior of the U.S. do not pursue the same curriculum as U.S.-trained D.O.'s. Their range of practice is limited primarily to musculoskeletal conditions and action of some other conditions using OMM and a variety of alternative medicine methods.