Osteopathic physicians, or DOs, are an off-shoot historically of allopathic physicians, or MDs. Although equally qualified medically, osteopathic physicians are especially trained in manual medicine, or osteopathic manipulative medicine. Osteopathic medicine was started in 1874 by A.T. Still. Dr. Still's focus in osteopathy was to increase the body's ability to heal itself. Allopathic physicians do not receive this training in medical school.
With the rise of popularity in alternative medicines, one of the biggest current debates is the efficacy of homeopathic medicine when contrasted with what we consider traditional, or allopathic medicine. While both schools of medicine have the common goal of healing the sick, both achieve that goal by different means.