DO stands for Doctor of Osteopathic Medicine. A physician with “DO” after their name has completed medical school, residency training, and licensing exams, just like a physician with “MD” (Doctor of Medicine) after theirs. Both are fully licensed to diagnose illness, prescribe medication, perform surgery, and practice in every medical specialty. The key difference is in their training: DOs receive additional instruction in a hands-on treatment approach and a philosophy that emphasizes treating the whole body as an interconnected system.
How DO Training Compares to MD Training
DO and MD students follow nearly identical paths. Both complete four years of medical school, with the first one to two years spent primarily in the classroom and the remaining time in clinical rotations. Both must pass national licensing exams. Both then enter residency programs in the specialty of their choice, training side by side in the same hospitals. Since 2020, DO and MD graduates have applied to residency through a single, unified matching system.
The main curricular difference is that DO students take additional coursework in the musculoskeletal system and learn a set of hands-on techniques called osteopathic manipulative treatment, or OMT. This training teaches them to use their hands to diagnose structural problems and treat pain by manipulating muscles, joints, and soft tissues.
What Osteopathic Manipulative Treatment Involves
OMT is the most distinctive tool in a DO’s training. During a session, the physician applies gentle pressure to stretch muscles and guide joints into proper alignment. Techniques range from slow, sustained pressure to quicker adjustments. You might be asked to hold and release your breath at specific points while the doctor repositions your limbs or works on soft tissue. Some DOs use thrust-based “popping” techniques similar to what a chiropractor does, though this is generally less common.
DOs most frequently use OMT for back, neck, and head pain. It’s also applied to a broader range of conditions: chronic pain from fibromyalgia or arthritis, breathing issues like asthma and sinus infections, bowel problems like IBS and constipation, sports injuries, repetitive stress injuries, carpal tunnel syndrome, and pregnancy-related discomfort such as swelling and sciatica. Not every DO uses OMT regularly in practice. Many specialize in fields like cardiology or emergency medicine where it plays little or no role in their daily work.
The Philosophy Behind Osteopathic Medicine
Osteopathic medicine rests on four core principles: the body is a unit of mind, body, and spirit; the body has a natural ability to heal and regulate itself; structure and function are deeply interconnected; and effective treatment follows from understanding all three of the above. In practical terms, this means DOs are trained to look beyond isolated symptoms and consider how different body systems influence each other. A DO treating chronic headaches, for example, might also evaluate posture, spinal alignment, and stress levels as contributing factors.
DO vs. MD in Patient Outcomes
A large study reviewed hospital data from 2016 to 2019 covering nearly 330,000 patients aged 65 and older. Among those treated by MDs, the mortality rate was 9.4%. Among those treated by DOs, it was 9.5%. Readmission rates were virtually identical (15.7% vs. 15.6%), average hospital stays were the same at four and a half days, and Medicare spending differed by just one dollar per patient. The researchers concluded that despite differences in medical school training and student demographics, there were no meaningful differences in cost or quality of hospital care between the two types of physicians.
Licensing and Practice Rights
DOs take a licensing exam called COMLEX-USA. Many also choose to take the USMLE, the same exam required of MD students, particularly if they’re applying to competitive residency programs. Both exams assess the same core competencies needed for safe patient care. Once licensed, DOs hold full practice rights in all 50 states, meaning they can practice any specialty, prescribe any medication, and perform any procedure an MD can.
Internationally, DOs trained in the United States have full practice rights in more than 65 countries. It’s worth noting that in some countries outside the U.S., the title “DO” refers to practitioners trained only in manual therapy rather than full medical practice, which can create confusion.
How Many DOs Practice in the U.S.
As of 2024, there are roughly 157,500 osteopathic physicians in the United States, making up about 11% of all practicing doctors. The profession is growing quickly: 28% of all current U.S. medical students are enrolled in osteopathic programs. This growth reflects both an expansion of DO medical schools and increasing acceptance of the degree across all specialties and hospital systems.
While DOs have historically been concentrated in primary care fields like family medicine and internal medicine, they now practice across the full spectrum of specialties, from orthopedic surgery to psychiatry to emergency medicine. The degree after a doctor’s name tells you something about their training philosophy, but in terms of what they’re qualified to do, a DO and an MD stand on equal footing.