The discipline of Internal Medicine originated in Germany and became popular in the United States in the early 20th century. The term is derived from Innere Medizin, denoting physicians who treated patients using their knowledge of laboratory science. Today, The American College of Physicians is the prime society for internal medicine globally.

Internal medicine doctors or internists primarily deal with adult patients and pay more attention to medicine for adults. They are associated with a patients right from teenage to old age and have a special residency-training period of three years on preventing and treating diseases that afflict adults. They work together with other medical specialists such as surgeons or pediatricians. Their ability to go about solving a health problem by looking at it from a number of angles is well known.

Internalists are equipped to handle simple as well as complicated health problems. They are good at deciphering diagnostic problems and dealing with multiple illnesses that occur simultaneously. They also educate their patients on general well being and advise them on preventive measures, substance abuse, womens health, mental well being and so on. As you can see, they are a highly trained group of medical practitioners.

Internal medicine doctors practice general internal medicine or further specialize other areas of internal medicine. There are 13 subspecialties from which they choose. Specialization is called fellowship. Some of the subspecialties are cardiology, gastroenterology, adolescent medicine, rheumatology (arthritis), and oncology. In the United States, The American Board of Internal Medicine and American Osteopathic Board of Internal Medicine certify internists.