DOs are physicians with a special focus on clinical medicine and the study of how the physical relationships between anatomical structures influence pathology, the natural history of an ailment, and treatment.
Though DOs can choose practice paths that either include or exclude the crux of the osteopathic philosophy (e.g., a new DO can choose whether or not to do manipulative medicine in their practice or just traditional allopathic medicine), most at least have a deeper understanding of the multifactorial approach to disease and treatment that goes beyond just prescribing medicine or rehab programs.
In my opinion, DO's make excellent primary care diagnosticians because of their training--many quite a bit better than traditionally trained allopaths. Training in anatomy and manipulative medicine is the perfect way to complement the skill set of a physician who works on longitudinal patient-centered problems (family med, peds, geriatrics, etc). I'm sure it also helps in understanding mechanisms of injury (ER, trauma) and the effects of tissue neoplasia (oncology). DOs, however, are typically less competitive in non-primary care residencies which primarily accept graduates from MD programs.
