A DO, or Doctor of Osteopathic Medicine, is a fully licensed physician who can diagnose, treat, prescribe medication, and perform surgery in all 50 U.S. states. DOs complete the same core medical training as MDs but receive additional education in the musculoskeletal system and hands-on treatment techniques. There are now more than 167,000 practicing DOs in the United States, making up roughly 11% of all physicians and over 25% of current medical students.
How DO Training Differs From MD Training
DO students attend four-year medical schools and study the same foundational sciences as their MD counterparts: anatomy, pharmacology, pathology, and clinical rotations in hospitals. The key difference is an additional 200 hours of training in the musculoskeletal system and a set of hands-on diagnostic and treatment methods known as osteopathic manipulative treatment, or OMT. This training teaches students to use their hands to identify restrictions in muscles, joints, and tissues and to treat them directly.
The philosophy behind osteopathic medicine rests on four core principles: the body functions as a connected unit of body, mind, and spirit; the body has built-in abilities to heal and regulate itself; structure and function are directly linked (meaning how your body is aligned affects how well it works); and effective treatment should account for all of these ideas together. In practice, this means DOs are trained to look beyond isolated symptoms and consider how the whole body contributes to a patient’s condition.
What Osteopathic Manipulative Treatment Looks Like
OMT is the most distinctive tool in a DO’s training. It includes several techniques, each suited to different problems. Muscle energy techniques involve the patient actively contracting specific muscles against the physician’s resistance to improve range of motion and reduce chronic pain. Myofascial release uses gentle, sustained pressure to release tightness in connective tissue, often for chronic low back pain or nerve-related disorders. High-velocity, low-amplitude techniques are quick, targeted thrusts to a joint, similar to what you might experience at a chiropractor’s office, used for acute back pain, neck pain, and certain headaches.
Other techniques address less obvious systems. Lymphatic pump methods use rhythmic pressure to improve immune function and help the body fight respiratory and gastrointestinal infections. Rib raising decreases stress-related nervous system activity and improves chest wall mobility, which can benefit patients with pneumonia. Cranial techniques use very light touch on the skull and are sometimes applied after concussions. Not every DO uses OMT in daily practice, particularly those in specialties like cardiology or psychiatry, but all are trained in it.
Licensing and Board Exams
DOs take a licensing exam called COMLEX-USA, which is recognized by every state medical licensing board in the country. MDs take the USMLE. The two exams measure overlapping but distinct knowledge. COMLEX includes questions on osteopathic principles and OMT, while the USMLE does not. Research shows scores on the two exams correlate strongly enough to make comparable estimates of a candidate’s overall ability, though the exams are not interchangeable. Many DO students choose to take both exams, particularly if they plan to apply to residency programs that historically trained only MDs.
Residency and Specialization
Until recently, DOs and MDs trained in separate residency systems. DOs had their own accrediting body (the AOA), while MDs trained in programs accredited by the ACGME. In 2020, these systems merged into a single accreditation standard under the ACGME. The goal was to create one unified quality benchmark for all residency training in the country.
The merger gave DO graduates access to a much larger pool of residency programs, but it came with trade-offs. About 26% of eligible osteopathic surgical programs either didn’t apply or withdrew from the new system, resulting in the loss of 41 surgical training programs during a period when the number of DO graduates was rapidly growing. Established ACGME surgical programs have historically favored graduates from MD schools, so integration into competitive surgical specialties remains a gradual process. That said, DOs practice in every medical specialty, from family medicine and pediatrics to orthopedic surgery and emergency medicine.
DO Practice Rights in the U.S. and Abroad
Within the United States, a DO license grants identical practice rights to an MD license. DOs prescribe medications, perform surgeries, admit patients to hospitals, and lead medical teams. In many clinical settings, patients may not even realize whether their physician holds a DO or MD degree.
International recognition has historically been more complicated. In some countries, “osteopath” refers to a non-physician practitioner who performs manual therapy, which created confusion about the credentials of American-trained DOs. That changed significantly in November 2023, when the International Association of Medical Regulatory Authorities approved a resolution recognizing U.S.-trained DOs as fully licensed physicians equivalent to MDs in 47 additional member countries. The resolution was submitted by the Federation of State Medical Boards and supported by the Association of Medical Councils of Africa.
The Growth of Osteopathic Medicine
Osteopathic medicine traces back to 1874, when Andrew Taylor Still, himself originally trained as an MD, developed a new approach to medicine that emphasized the body’s structural integrity and self-healing capacity. He founded the first osteopathic medical school in 1892 in Kirksville, Missouri. For much of its history, osteopathic medicine occupied a smaller, sometimes marginalized corner of American healthcare.
That has changed dramatically. The number of DOs and osteopathic medical students in the U.S. recently surpassed 200,000 combined. More than one in four medical students in the country now attends a DO school. This growth reflects both an expansion of osteopathic medical schools and increasing demand for primary care physicians, a field where DOs have traditionally been well represented. While DOs work across all specialties, their training’s emphasis on whole-body assessment and hands-on treatment continues to attract students drawn to a more integrative approach to patient care.