Medical specialty that deals with the diagnosis and medical, as opposed to surgical, treatment of diseases of adults.
It is broadly identical with the practice of the physician, as opposed to that of the surgeon. It deals with the entire patient rather than a particular organ system and is, in effect, the parent of other medical specialties, such as cardiology, dermatology, and gastroenterology.

An advanced practitioner of internal medicine is called an internist in many countries.
Professional qualifications for certification include graduation from an approved medical school, followed by an internship of not less than one year and, further, a prolonged program of intensified training and experience. The core of the prolonged program consists of two to three years of full-time residency training in a hospital.
Additional study in the program may be devoted to work in any clinical, investigative, or basic science field related to internal medicine. The training program for internists emphasizes advanced knowledge of anatomy, microbiology, biochemistry, pathology, pharmacology, and physiology.

Encyclopædia Online Britannica. Internal medicine. Accessed on October 26, 2009. Internet.