A DO is a fully licensed physician. The initials stand for Doctor of Osteopathic Medicine, and DOs can diagnose illness, prescribe medication, perform surgery, and practice in every medical specialty, just like an MD. There are roughly 167,000 DOs practicing in the United States today, making up about 11% of all physicians in the country.
The distinction between a DO and an MD comes down to training philosophy and a few hundred extra hours of hands-on coursework. In practical terms, you may never notice a difference in the care you receive. But understanding what sets a DO apart can help you make more informed choices about your healthcare.
How DO Training Differs From MD Training
DO and MD students cover the same core medical sciences: anatomy, pharmacology, pathology, clinical rotations in hospitals. The major difference is that osteopathic medical schools add approximately 200 extra hours of training focused on the musculoskeletal system. This coursework teaches students to use their hands to diagnose and treat problems in muscles, bones, and joints through a set of techniques collectively called osteopathic manipulative treatment, or OMT.
Beyond the hands-on training, osteopathic education is built around four principles: the body works as a connected unit of body, mind, and spirit; the body has a built-in capacity to heal and regulate itself; the structure of the body and how it functions are deeply linked; and effective treatment accounts for all three of those ideas together. In practice, this means DOs are trained to look beyond the specific symptom that brought you in and consider how other systems in your body might be contributing.
DO students attend four-year osteopathic medical schools. There are currently 44 colleges of osteopathic medicine spread across 71 campuses in the U.S., and enrollment is growing fast. More than 25% of all medical students in the country are now in osteopathic programs, and women make up over 55% of those students.
What Osteopathic Manipulative Treatment Looks Like
OMT is the skill that most clearly separates a DO from an MD. It involves the physician using their hands to stretch, apply gentle pressure, or reposition parts of your body. The most common techniques include myofascial release (sustained pressure on connective tissue to relieve tightness), soft tissue manipulation (similar to targeted massage), counterstrain (positioning your body to relieve tender points), and muscle energy (where you actively push against the doctor’s resistance to improve joint mobility).
The most frequent use of OMT is for back pain. A randomized controlled trial of OMT for acute low back pain found significant reductions in pain and increased patient satisfaction compared to standard care like medication and physical therapy. OMT has also shown meaningful results for neck-related headaches, with one study reporting clinically significant improvements in 23 of 24 measures of neck range of motion along with reduced pain and anxiety. Not every DO uses OMT regularly in their practice, though. A DO who specializes in cardiology or psychiatry may rarely perform these techniques, while one in family medicine or sports medicine might use them daily.
Licensing, Board Exams, and Residency
DOs take the COMLEX-USA licensing exam, which is recognized by all state medical licensing boards. Many DO students also take the USMLE, the same exam required of MD students. In one study of osteopathic medical students, 87% took both exams. Research shows the two tests measure similar competencies, though they aren’t identical: COMLEX includes questions on osteopathic principles that the USMLE does not.
After medical school, DOs complete residency training in their chosen specialty. Since 2020, all residency programs in the U.S. fall under a single accreditation system run by the ACGME. This means DO and MD graduates now apply to and train in the exact same residency programs, held to the same standards. Before this merger, osteopathic and allopathic residencies were accredited separately, which sometimes limited where DO graduates could train. That barrier no longer exists.
Specialties DOs Practice In
DOs work in every field of medicine. While a large number practice in primary care, including family medicine, internal medicine, and pediatrics, DOs also become surgeons, anesthesiologists, emergency physicians, psychiatrists, dermatologists, and cardiologists. There is no medical specialty closed to a DO. The degree carries the same legal authority as an MD to practice medicine and surgery in all 50 states.
Practice Rights Outside the U.S.
In more than 65 countries, U.S.-trained DOs have full practice rights, meaning they can work as physicians just as they would at home. However, outside the United States, the title “DO” can mean something very different. In some countries, osteopathic training focuses only on manual manipulation, and practitioners do not have the authority to prescribe medication or perform surgery. Only U.S.-trained DOs complete the full scope of medical education that qualifies them as licensed physicians. If you’re seeing a DO in the U.S., you’re seeing a doctor with the same clinical authority as any MD.
DO vs. MD: What It Means for Your Care
For most patients, the experience of seeing a DO and seeing an MD will feel very similar. Both can order imaging, run bloodwork, prescribe drugs, refer you to specialists, and admit you to the hospital. The philosophical difference is that DOs are specifically trained to think about how your body’s structure relates to its function and to consider your overall health rather than focusing only on the organ system in question. Whether that translates into a noticeably different office visit depends on the individual doctor and their specialty.
The practical advantage of choosing a DO is the option of OMT. If you have chronic back pain, recurring headaches, or musculoskeletal issues, a DO may offer hands-on treatment as part of your care plan alongside or instead of medication. If you’re seeing a DO for something unrelated to musculoskeletal health, your experience will likely be indistinguishable from seeing an MD. Either way, the credentials, training length, and licensing standards ensure you’re in the hands of a fully qualified physician.