Internal medicine is the medical specialty dealing with the prevention, diagnosis, and treatment of adult diseases. Physicians specializing in internal medicine are called internists. They are especially skilled in the management of patients who have undifferentiated or multi-system disease processes. Internists care for hospitalized and ambulatory patients and may play a major role in teaching and research.

The term internal medicine comes from the German term innere Medizin, popularized in Germany in the late 19th century to describe physicians who combined the science of the laboratory with the care of patients. Many early-20th-century American doctors studied medicine in Germany and brought this medical field to the United States. Thus, the name "internal medicine" was adopted in imitation of the existing German term. Specialists in internal medicine are commonly called internists in the United States. Elsewhere, especially in Commonwealth nations, such specialists are often simply called physicians. Because their patients are often seriously ill or require complex investigations, internists do much of their work in hospitals.


Definition of an internist

Internists are qualified physicians with postgraduate training in internal medicine and should not be confused with "interns," who are doctors in their first year of residency training. Although internists may act as primary care physicians, they are not "family physicians," "family practitioners," or "general practitioners," whose training is not solely concentrated on adults and may include surgeryobstetrics, and pediatrics. The American College of Physicians defines internists as "physicians who specialize in the prevention, detection and treatment of illnesses in adults".

Education and training of internists

The training and career pathways for internists vary considerably across the world. First, they must receive the "entry-level" education required of any medical practitioner in the relevant jurisdiction. The entry-level for medical education programs are tertiary-level courses, undertaken at a medical school attached to a university.

Programs that require previous undergraduate education are usually four or five years in length. Hence, gaining a basic medical education may typically take eight years, depending on jurisdiction and university. Following completion of entry-level training, newly graduated medical practitioners are often required to undertake a period of supervised practice before the licensure, or registration, is granted, typically one or two years. This period may be referred to as, "internship" or "conditional registration." Then, internists require specialist training in internal medicine or one of its subspecialties. In North America, this postgraduate training is often referred to as residency training; in Commonwealth countries, such trainees are often called registrars.

Subspecialties of internal medicine

In the United States, two organizations are responsible for certification of subspecialists within the field: the American Board of Internal Medicine and the American Osteopathic Board of Internal Medicine.

American Board of Internal Medicine

The following are the subspecialties recognized by the American Board of Internal Medicine.

Internists may also specialize in "allergy" and "immunology." The American Board of Allergy, Asthma, and Immunology is a conjoint board between internal medicine and pediatrics.

American College of Osteopathic Internists

The American College of Osteopathic Internists recognizes the following subspecialties.

Medical diagnosis and treatment

Medicine is mainly focused on the art of diagnosis and treatment with medication, but many subspecialties administer surgical treatment:



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