The letters D.O. seen after a doctor's name refer to the title Doctor of Osteopathy. Osteopathic doctors specialize in much the same areas as regular medical doctors. The main differences between standard physicians and doctors of osteopathy is in how they practice medicine. Osteopathic doctors are known to treat the whole person and not just the disease. They also tend to practice in areas of the world where regular physicians may be scarce.
The initials D.O. after a doctor's name stands for Doctor of Osteopathic Medicine. This is a branch of the medical profession within the United States. D.O.s have the same rights and privileges as MDs.