The abbreviation D.O. stands for Doctor of Osteopathic Medicine, representing one of the two types of fully licensed physicians in the United States. A D.O. graduate is a medical doctor who has attended an accredited osteopathic medical school and possesses the same rights and privileges as an M.D. physician, including the ability to diagnose, treat, and prescribe medication across all 50 states. The D.O. degree integrates the full scope of modern medicine with a distinct, whole-person philosophy of care.
The Meaning of D.O.: Doctor of Osteopathic Medicine
The D.O. degree was established by physician Andrew Taylor Still in the late 19th century, with the first school opening in Missouri in 1892. This system of medicine was founded on the idea that the body’s structure and function are intricately related, and that the body possesses natural healing mechanisms. Today, a Doctor of Osteopathic Medicine is often referred to as an osteopathic physician, practicing in every medical specialty.
Osteopathic physicians provide comprehensive medical care, utilizing all the tools of modern medicine, such as prescribing drugs, ordering diagnostic tests, and performing surgery. Their education and licensure requirements ensure they are trained to the same standards as their M.D. colleagues. The profession has experienced significant growth, now representing over 11% of all physicians in the U.S. and over 25% of all medical students.
Core Principles of Osteopathic Medicine
The foundation of the D.O. approach rests on four philosophical tenets that guide the physician’s diagnostic and treatment decisions. These principles emphasize the body’s natural healing mechanisms and the interconnectedness of its systems.
The four core principles are:
- The body is a single, dynamic unit, combining body, mind, and spirit.
- The body possesses an inherent capacity for self-regulation, self-healing, and health maintenance.
- Structure and function are reciprocally interrelated.
- Rational treatment is based upon an understanding of these three interconnected concepts.
Osteopathic Manipulative Treatment
Osteopathic Manipulative Treatment (OMT) is a specific hands-on technique that distinguishes the D.O. approach. OMT is a therapeutic application used to diagnose, prevent, and treat illness and injury, specifically addressing somatic dysfunction involving impaired function of the musculoskeletal system.
OMT techniques are varied and include gentle stretching, sustained pressure, and precision thrusts to manipulate joints and soft tissues. This manual medicine restores motion, reduces pain, and enhances the body’s overall function by improving circulation and nerve signaling. OMT supports the body’s self-healing mechanisms and is often integrated alongside conventional medical treatments.
How D.O.s and M.D.s Compare
D.O.s and M.D.s are functionally equivalent in the United States, sharing identical practice rights. Both complete four years of medical school followed by residency training lasting between three and eight years, depending on the specialty. Since 2020, both D.O. and M.D. graduates apply for the same residency programs accredited by the Accreditation Council for Graduate Medical Education (ACGME).
The primary difference lies in the educational curriculum and philosophical emphasis. D.O. students receive an additional 300 to 500 hours of training focused on the musculoskeletal system and OMT. This training reinforces the osteopathic physician’s perspective on the body as an interconnected system. While M.D.s focus on a conventional allopathic model, D.O.s embrace a more holistic and preventive philosophy, considering the patient’s lifestyle and environment beyond immediate symptoms.
The Path to Becoming a D.O.
The educational journey begins with a pre-medical undergraduate degree, followed by the four-year program at a College of Osteopathic Medicine. Prospective students apply through the American Association of Colleges of Osteopathic Medicine Application Service (AACOMAS). Admission requirements include prerequisite science coursework and the Medical College Admission Test (MCAT).
During medical school, D.O. students complete the same basic science and clinical rotations as M.D. students, along with dedicated OMT training. For licensure, D.O. students must pass the Comprehensive Osteopathic Medical Licensing Examination of the United States (COMLEX-USA). Many also take the United States Medical Licensing Examination (USMLE) for residency applications. Upon graduation, D.O.s enter an accredited residency program for specialty training.
Practice and Specialties of D.O.s
Osteopathic physicians practice across the entire spectrum of medicine and surgery, from neurosurgery to dermatology. Many D.O.s choose primary care fields, with a high percentage practicing in specialties like family medicine, internal medicine, and pediatrics. This tendency aligns with their training, which emphasizes preventive care and a whole-person approach.
D.O.s serve in hospitals, private practices, and prominent roles, including Physician to the President of the United States. In the clinical setting, a patient may not notice a difference in service delivery, as both D.O.s and M.D.s utilize evidence-based medicine. However, the D.O. retains the option to incorporate manual techniques and a distinct philosophical perspective into patient care.