Comparison of allopathic and osteopathic physicians in the United States
This article discusses similarities and differences between allopathic and osteopathic physicians in the United States.  For the sake of comparison, holders of an M.D. are sometimes referred to as allopathic physicians, while those with a D.O. are known as osteopathic physicians.

# Differences in the United States
There is disagreement on the differences between osteopathic and allopathic medicine. According to the Cecil Textbook of Medicine, 22 ed., "other than teaching manipulation, undergraduate medical training for an osteopathic degree (D.O.) is now virtually indistinguishable from that which leads to the M.D. degree. Osteopathic physicians complete conventional residencies in osteopathic or allopathic hospitals and training programs; are licensed in all states; and have rights and responsibilities, such as military service, that are identical to allopathic physicians and surgeons."
Harrison's Principles of Internal Medicine, 16th ed., makes a similar comparison.

## History
There is a history of hostility between the allopathic and osteopathic worlds, though animosity between the groups has subsided in recent years.  In 2005, the president of the Association of American Medical Colleges wrote,

## Demographics
The gender and racial distribution of allopathic and osteopathic practitioners are similar.
There are significantly more allopathic physicians than osteopathic physicians.   In 2004, 17,000 students matriculated as first-year students at allopathic medical students while 3,800 students matriculated at Osteopathic schools, a ratio of 5 allopathic students for every osteopathic one.

### Changing numbers
Between 1980 and 2005, the number of yearly allopathic graduates remained virtually constant at around 16,000.  During the same period, the number of osteopathic graduates increased by more than 250% (from about 1,150 to about 2,800).  Osteopathic graduates are expected to increase to 3,300 by the year 2010 and as many as 4,000 by 2015. The number of allopathic graduates per 100,000 fell from 7.5 to 5.6, while the number of osteopathic graduates per 100,000 rose from 0.4 to 0.8.

## Cultural differences
Some authors describe less quantifiable distinctions between the two.  Avery Hurt writes, "In actual practice, the variations between the two types of physicians are often so slight as to be unnoticeable to patients, and a day in the life of each can appear indistinguishable. But the differences are there, subtle but deep." Several studies have investigated these differences.  One compared the patient interactions of allopathic and osteopathic physicians.  The study found that "osteopathic physicians were more likely to use patient's first names and to discuss the social, family and emotional impact of illnesses." For example, "66% of DOs discussed a patient's emotional state compared with about one-third of MDs."  The same study found that "allopathic physicians scored higher in discussing literature or scientific basis of treatment."  However, a much larger study analyzed 341.4 million patient visits to general and family medicine specialists in the United States, including 64.9 million (19%) visits to osteopathic physicians and 276.5 million (81%) visits to allopathic physicians.  It found that there was no significant difference between allopathic and osteopathic physicians "with regard to time spent with patients and preventive medicine services."
A Harvard study found significant differences in the attitudes of members of the osteopathic and allopathic communities.  The study found that 40.1% of allopathic students and physicians described themselves as "socioemotionally" oriented over "technoscientific" orientation. 63.8% in the osteopathic community self-identified as socioemotional. (p < .0001)
One study of osteopathic physicians attempted to investigate their perceptions of differences in philosophy and practice between themselves and their allopathic counterparts.  88% of the respondents had a self-identification as osteopathic physicians, but less than half felt their patients identified them as such.  Further, the study found that "not a single philosophic concept or resultant practice behavior had concurrence from more than a third of the respondents as distinguishing osteopathic from allopathic medicine."
As the training of osteopathic and allopathic physicians become less distinct, some have expressed concern that their unique characteristics will be lost.  Others welcome the merger and already label "allopathic medicine" as "the type of medicine practiced by M.D. and D.O. type doctors."   One persistent difference is the respective acceptance of the terms "allopathic" and "osteopathic."  Osteopathic medical organizations and medical schools all include the word osteopathic in their names, and such groups actively promote an "osteopathic approach" to medicine.  This is in sharp contrast with the term allopathic.  No major medical society or medical school includes the word allopathic in its title, nor do they promote an allopathic approach to medicine.  However, as interest in alternative medical therapies increases, the term allopathic has been used by the medical profession to describe conventional medical practices - an acceptance which many have criticized.

## Medical education and training

### Medical schools
An independent board of the AMA, the Association of American Medical Colleges (AAMC) accredits the 125 U.S. allopathic medical schools, while an independent board of the American Osteopathic Association (AOA) (COCA) accredits the 26 U.S. osteopathic medical schools.  There are only two U.S. universities that have accredited programs in both allopathic and osteopathic medicine - Michigan State University and the University of Medicine and Dentistry of New Jersey.
Many authors note the most obvious difference between the curricula of osteopathic and allopathic medical schools, Osteopathic Manipulative Medicine (OMM), a type of manual therapy taught at only osteopathic schools.  A Harvard medical school faculty reviewed report lists several types of injuries and illnesses in which evidence-based studies suggest OMM may provide some benefit.  A 2001 survey of osteopathic physicians found that more than 50% of the respondents used OMT on less than 5% of their patients. The survey was the latest indication that osteopathic physicians have become more like allopathic physicians in all respectsfewer perform OMT, more prescribe drugs, and many perform surgery as a first option.
Some authors note the differences in the GPA's and MCAT scores of those who matriculate at Osteopathic schools.  In 2007, the average MCAT score and GPA was 28 and 3.5 for allopathic applicants and 25.3 and 3.5 for osteopathic applicants. One study found that as many as one third of students at osteopathic schools had been rejected by an allopathic school.  In addition, osteopathic students have a failure rate three time greater than allopathic students on the United States Medical Licensing Exam (USMLE). (It should be noted that osteopathic students are required to take the Comprehensive Osteopathic Medical Licensing Examination (COMLEX) and  that the USMLE  can be taken in addition to the COMLEX.  Allopathic students however are not allowed to take the COMLEX)  However, the same study notes that "despite correlations between MCATs and Step 1 licensing exams, correlations between the latter and clinical performance are weak. Performance as a physician correlates better with proficiency in the humanities and with personal characteristics such as motivation, conscientiousness,
integrity, empathy, and a robust psychological constitution."  The author notes that the "better performance  on their own National Board of Osteopathic Medical Examiners (NBOME) exam has been attributed to its greater emphasis on clinical context."

### Residency
In contrast to medical school accreditation, the boundaries between allopathic and osteopathic residency programs are more flexible.  The Accreditation Council for Graduate Medical Education (ACGME) describes the residency programs it oversees as training in allopathic medicine. Graduates of both osteopathic and allopathic medical schools are eligible to apply to these programs through the National Residency Matching Program (NRMP).  In 2003, 99% of US allopathic and 43% of osteopathic graduates went on to train in allopathic residency programs.
The American Osteopathic Association accredits osteopathic residency programs.  There have been calls to end the remaining barriers between the two types of programs. Since 1985, a single residency training program can be dual-accredited by both the ACGME and the AOA, and such programs are called combined allopathic/osteopathic residencies.
In 2001, the AOA adopted a provision making it possible for a resident in any allopathic program to apply for osteopathic approval of their training. The topic of dual-accreditation is controversial.  Opponents claim that by merging osteopathic students into the "allopathic world," the unique quality of osteopathic philosophy will be lost.  Supporters claim the programs are popular because of the higher prestige and higher resident reimbursement salaries associated with allopathic programs. Allopathic graduates are generally not permitted to training in osteopathic residencies, except under special circumstances. The two largest traditionally allopathic organizations, the American Medical Association and the American Medical Student Association, both support further integration and non-discrimination in residency programs.
The number of osteopathic students entering ACGME residencies increased every year from 1999-2004, while the number in AOA-accredited programs fell.  In 2000, 4175 osteopathic graduates were training in ACGME programs, versus 2781 in AOA programs.
There are notable differences in the specialty choices of allopathic and osteopathic medical graduates.  One study attributes this to a difference in the 'cultures' of allopathic and osteopathic school. "In comparison with allopathic schools, the cultural practices and educational structures in osteopathic medical schools better support the production of primary care physicians." According to one survey, 54.6% of deans of allopathic medical schools reported that training future primary care physicians was more important to their institutions than training future specialist physicians, compared with 100% of osteopathic medical school deans. (F = 893.11,95, p < .0001).
Recent trends show osteopathic graduates entering specialty historically dominated by allopathic graduates. A JAMA study found that "In 1996-1997, 624 DOs made up 2.9% of the total GY1 residents without prior . By 2002-2003, their numbers had more than doubled to 1312, and DOs represented 6.0% of GY1s without prior GME."
Between 1997-01, the number of osteopathic graduates matching into anesthesiology almost doubled every year - from fewer than 10 to over 100 over the course of 4 years.
Some authors have described concerns within the osteopathic profession about the increasing number of DOs seeking allopathic GME. Not only are there more DOs training solely in ACGME-accredited programs and thus bypassing American Osteopathic Association (AOA)-accredited programs, but there are now more than 900 dually accredited programs, wherein the resident trains in the AOA-accredited internship and then transfers directly into an allopathic program.

### Licensure

### Continuing medical education
To maintain a license to practice medicine, U.S. physicians are required to complete addition training every few years, so called continuing medical education, CME.  There are subtle differences in the CME requirements for allopathic and osteopathic physicians, and in how these CME credits are approved.  The requirements for maintaining a physician license for allopathic or osteopathic physicians are almost identical in most states, though there are small differences. For example, in the case of Pennsylvania, allopathic licenses begin on December 31, whereas osteopathic ones begin on October 31.

## Symbols
Some osteopathic organizations use the rod of Ascelpius, a symbol of healing through medicine consisting of a single serpent entwined around a staff.  Allopathic organization also use the rod of Asclepius, and another symbol, the caduceus, consisting of two intertwining snakes.