Osteopathic medicine originated in the 1870 s by a physician, Dr. Andrew T. Still, who was disheartened with standard medical practice at that time. His idea was to focus on the musculoskeletal system of the body, believing that manipulation of this system, along with changes in diet and lifestyle, would stimulate the body s own recuperative powers. The idea is to treat the "whole person," rather than simply focusing on specific illnesses. It is therefore claimed to be a more holistic approach to wellness than regular (sometimes called allotropic) medicine.
The basic curriculum in the two types of medical schools is the same. However, D.O. schools also teach body manipulation (300 - 500 hours of additional training in the musculoskeletal system) and have a holistic, preventative philosophy toward health care. Osteopathy schools mission is to train primary care physicians (e.g. specializing in family practice, internal medicine, pediatrics) but D.O. students can apply for residencies in other specialties. If you decide to apply to D.O. schools, you need to know about the difference in education and philosophy from the M.D. schools.
"Approximately 65% of practicing osteopathic physicians specialize in primary care areas, such as pediatrics, family practice, obstetrics and gynecology, and internal medicine." ( American Osteopathic Association). The prerequisites for attending schools of osteopathic medicine are very similar to allopathic medical schools, but the average GPA of those applying to osteopathic schools is a bit lower (3.35 overall, 3.20 BCPM GPA (Bio., Chem., Math. & Physics), and the MCAT average is also lower (23.4). "Generally, MCAT scores and grade point averages are slightly higher for matriculating students than scores reported for the overall applicant pool." One of the general admission requirements that is different from those of allopathic schools is that the applicant has shadowed an osteopathic physician. You can read more about admission requirements here.
Students interested in an osteopathic medical program may apply to a D.O. program through the AACOMAS application affiliated with the American Association of Colleges of Osteopathic Medicine. There are 28 osteopathic schools in the United States, as opposed to 133 allopathic (or regular) MD schools.