A Doctor of Osteopathy, now formally called a Doctor of Osteopathic Medicine (DO), is a fully licensed physician who can diagnose, treat, prescribe medication, and perform surgery in all 50 U.S. states. DOs receive the same scope of training as MDs but with additional coursework in hands-on musculoskeletal techniques and a philosophy that emphasizes treating the whole person rather than isolated symptoms. As of 2024, more than 157,000 DOs practice in the United States, making up about 11% of all American physicians.
Core Philosophy of Osteopathic Medicine
Osteopathic medicine is built on four tenets, as defined by the American Osteopathic Association. First, the body is a unit: a person is an integrated whole of body, mind, and spirit. Second, the body is capable of self-regulation, self-healing, and maintaining its own health. Third, structure and function are interrelated, meaning that problems in the musculoskeletal system can affect other organ systems and vice versa. Fourth, effective treatment must account for all three of those principles together.
In practical terms, this means a DO treating someone with chronic headaches might look beyond the head itself, examining posture, spinal alignment, stress levels, and sleep patterns as contributing factors. The approach aligns with what researchers call the biopsychosocial model, which considers physical, psychological, social, and even spiritual dimensions of a person’s health rather than focusing solely on the disease.
How DO Training Compares to MD Training
DO students attend four-year medical schools accredited by the Commission on Osteopathic College Accreditation. Their curriculum covers the same core sciences as MD programs: anatomy, biochemistry, pharmacology, pathology, and clinical rotations in hospitals and clinics. The key difference is additional training in osteopathic principles and practice, which includes learning hands-on diagnostic and treatment techniques for the musculoskeletal system.
After medical school, DOs complete residency training just like MDs. A major shift happened in 2020, when the Accreditation Council for Graduate Medical Education completed a six-year effort to create a Single Accreditation System for all residency and most fellowship programs in the country. Before this change, DO and MD graduates applied to separate residency systems. Now all residents are eligible to apply to all programs, regardless of whether they hold a DO or MD degree. This unified system means a DO can train at any hospital or academic medical center in the country.
Licensing Exams for DOs
DO graduates must pass the Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA). Their medical schools are required to have students pass the first two portions of this exam as a condition of accreditation. COMLEX is the only licensing exam accepted for osteopathic physician licensure in every U.S. jurisdiction.
That said, about 60% of osteopathic medical students also take at least one portion of the USMLE, the licensing exam used by MD graduates. They often do this to strengthen residency applications at programs more familiar with USMLE scores. Only six states (California, Florida, Oklahoma, Michigan, Pennsylvania, and West Virginia) specifically require COMLEX for initial DO licensure. All other state boards accept either exam. No state requires both.
Osteopathic Manipulative Treatment
The most distinctive clinical skill DOs learn is osteopathic manipulative treatment, or OMT. This is a set of hands-on techniques used to diagnose and treat musculoskeletal problems, improve circulation, and relieve pain. Not every DO uses OMT in daily practice, but all are trained in it. Two of the most common techniques illustrate how it works.
High-velocity, low-amplitude thrust (HVLA): A quick, targeted force applied over a short distance to a joint that isn’t moving properly. The rapid stretch of a contracted muscle sends signals to the nervous system, which responds by telling that muscle to relax. This can decrease joint pain and improve range of motion. It’s similar to what you might experience during a chiropractic adjustment.
Myofascial release: A slower, gentler technique that works on fascia, the connective tissue that surrounds muscles and organs. The physician follows the tissue in its direction of ease, gradually releasing tension to improve blood flow and reduce pain. It can be used for conditions ranging from back pain to tension headaches.
DOs may use OMT as a standalone treatment or alongside medications, physical therapy, or other interventions depending on the patient’s needs.
What Specialties DOs Practice In
Osteopathic medicine has historically been associated with primary care, and DOs do gravitate toward family medicine, internal medicine, and pediatrics at higher rates than MDs. But the profession has diversified significantly. DOs now work across the full range of medical and surgical specialties, including cardiology, orthopedic surgery, emergency medicine, psychiatry, and neurology.
Across all U.S. physicians, roughly 37% work in primary care, 34% in medical specialties, and 29% in surgical specialties. DOs follow a broadly similar distribution, though their primary care numbers tend to skew slightly higher. The expansion into every specialty has accelerated since the residency systems merged in 2020, giving DO graduates equal access to competitive subspecialty programs.
DOs Outside the United States
U.S.-trained DOs have full practice rights in more than 65 countries, meaning they can practice medicine with the same authority they hold domestically. This is an important distinction from non-physician osteopaths in countries like the United Kingdom, Australia, and parts of Europe, where “osteopath” refers to a manual therapy practitioner who is not a medical doctor. A U.S. DO is a physician first, with optional expertise in manual techniques on top of full medical training.
DO vs. MD: What the Difference Means for Patients
For most patients in most clinical situations, the experience of seeing a DO versus an MD is nearly identical. Both can order tests, prescribe any medication, perform surgery, and manage complex conditions. The differences are philosophical and subtle. A DO may be more likely to incorporate hands-on examination of the musculoskeletal system into a routine visit, or to frame a treatment plan around how different body systems interact with each other rather than treating one organ in isolation.
These differences are most visible in primary care and musculoskeletal medicine, where OMT techniques can be directly applied. In a surgical suite or an ICU, the practical gap between a DO and an MD essentially disappears. What matters far more than the two letters after a physician’s name is their residency training, clinical experience, and individual approach to patient care.