A DO is a Doctor of Osteopathic Medicine, a fully licensed physician who can practice every branch of medicine, prescribe medications, and perform surgery. There are more than 157,000 DOs practicing in the United States today, making up about 11% of all U.S. physicians. In practical terms, a DO has the same authority and responsibilities as an MD. The difference lies in their training philosophy and one additional skill set they learn in medical school.
How DO Training Differs From MD Training
DO and MD programs have virtually the same admission criteria, weighing GPA and MCAT scores heavily. Both follow the same basic structure: roughly the first one to two years in the classroom studying anatomy, physiology, pharmacology, and pathology, followed by clinical rotations in hospitals and clinics. A DO student completes four years of medical school, then enters residency training just like an MD graduate.
The key addition in osteopathic medical schools is training in osteopathic manipulative treatment, or OMT. This is a set of hands-on techniques where physicians use their hands to diagnose, treat, and prevent illness or injury by moving a patient’s muscles and joints. Think of it as a structured system of manual therapy built into a full medical education. DO students learn these techniques alongside all the same coursework their MD counterparts complete.
The Osteopathic Philosophy
Osteopathic medicine is built on four principles that shape how DOs are trained to think about patient care. The first is that the body is a unit of body, mind, and spirit, meaning symptoms in one area can reflect problems elsewhere. The second is that the body is capable of self-regulation and self-healing. The third is that structure and function are connected: the way your body is physically aligned affects how well it works. The fourth follows from the others: effective treatment should account for all of these relationships rather than targeting symptoms in isolation.
In day-to-day practice, this philosophy translates into what’s often described as a “whole-person” approach. A DO treating chronic back pain, for instance, might look beyond the spine itself to consider posture, stress, sleep habits, and how the pain connects to the patient’s overall health. That said, many MDs practice with a similarly holistic mindset. The distinction is that osteopathic schools formally embed this framework into every stage of training.
What Osteopathic Manipulative Treatment Involves
OMT is the most visible difference between DOs and MDs. It includes techniques like stretching muscles and connective tissue, applying gentle pressure to joints, and guiding the body through specific ranges of motion. These methods are used most commonly for musculoskeletal pain, and the evidence shows that manual therapy is equally or more effective than oral pain medications for treating pain and improving function.
Some DOs also use OMT to support treatment of conditions outside the musculoskeletal system, including cardiovascular disease and metabolic disorders like diabetes. Not every DO uses OMT regularly in practice, though. A DO who specializes in cardiology or emergency medicine may rarely use hands-on techniques, while one in family medicine or sports medicine might use them daily.
Licensing Exams and Residency
DO graduates take the COMLEX-USA licensing exam, which covers the same core medical content as the USMLE (the exam MD graduates take) plus additional material on osteopathic manipulative medicine. Many DO students choose to take both exams, since some residency programs weigh USMLE scores more heavily in their selection process. In certain primary care specialties and regions with a strong osteopathic tradition, like Ohio, COMLEX scores alone are widely accepted.
Until recently, DO graduates and MD graduates trained in separate residency systems. That changed with a major transition completed in 2020, when the U.S. moved to a single accreditation system for all medical residencies. Now, DO and MD graduates compete for the same residency positions and are held to the same training standards. During the transition, 98% of previously osteopathic-only residency programs that applied successfully achieved accreditation under the unified system.
What a DO Can and Cannot Do
In every U.S. state, DOs have full, unrestricted medical practice rights identical to MDs. They can specialize in anything from neurosurgery to psychiatry to pediatrics. They hold hospital privileges, lead medical teams, and serve in every branch of the military’s medical corps. More than 65 countries outside the U.S. also grant DOs full practice rights.
This is worth emphasizing because a common point of confusion is the difference between a U.S.-trained DO and an osteopath in other countries. In places like the U.K. and Australia, an “osteopath” is a non-physician practitioner who focuses exclusively on manual therapy and cannot prescribe medication or perform surgery. A U.S. Doctor of Osteopathic Medicine is a completely different credential: a fully trained physician first, with manual therapy skills layered on top.
How Osteopathic Medicine Started
Osteopathic medicine was founded by Andrew Taylor Still, a physician and Civil War surgeon who grew disillusioned with 19th-century medical practices after losing family members to disease. He became convinced that many conditions could be treated by finding and correcting physical problems that interfered with the body’s natural healing processes. In 1892, he opened the American School of Osteopathy in Kirksville, Missouri, in a two-room building. From that single school, the profession has grown to produce roughly one in four new medical students in the U.S. today.
Choosing Between a DO and an MD
For patients, the practical difference between seeing a DO and an MD is often minimal. Both go through comparable training, pass rigorous licensing exams, and complete the same residency programs. The most meaningful distinction is that a DO may be more likely to incorporate hands-on techniques into your care and may approach diagnosis with an explicit focus on how different body systems interact. If you’re looking for a physician who offers OMT alongside standard medical care, seeking out a DO specifically makes sense. Otherwise, the quality of your care depends far more on the individual physician’s experience and skill than on the two letters after their name.