Internal Medicine


Internal medicine is the medical specialty that focuses on the care of adult patients, and internal medicine physicians (called "internists") are specialists who apply scientific knowledge and clinical expertise to the diagnosis, treatment, and compassionate care of adults across the spectrum from health to complex illness.

Internal medicine is the world’s largest medical specialty, with nearly 200,000 internists practicing in the United States. Clinically, internal medicine physicians practice in an extremely wide range of roles and settings:

  • Internists are trained in the comprehensive care of patients and may function as generalist physicians practicing primary care, hospital medicine, or both.

  • Internists may also undergo additional training to focus their practice in one of the recognized subspecialty areas within internal medicine (i.e. cardiology, pulmonology, oncology, etc.)

  • Internal medicine also carries a strong emphasis on research. Internists may be involved in basic science discovery, but also are prominent in translating basic science knowledge to clinical practice. As a specialty, up to two-thirds of all clinical research funding through the National Institutes of Health (NIH) is awarded to internists, and Departments of Medicine occupy a key role in research at our nation’s academic medical centers.

  • Medical education is also an important activity undertaken by internists as the nature of internal medicine and its wide-ranging clinical and research activities equip internists well to teach medical students, residents, and fellows.





















At least three of their seven or more years of medical school and postgraduate training are dedicated to learning how to prevent, diagnose, and treat diseases that affect adults. This basic training qualifies them to practice internal medicine, and you may see these physicians referred to by several terms, including "internists" or "doctors of internal medicine." But don't mistake them with "interns," who are doctors in their first year of residency training. Internists are sometimes referred to as the "doctor's doctor," because they are often called upon to act as consultants to other physicians to help solve puzzling diagnostic problems.

Many internists enter into practice following completion of their basic internal medicine training. These physicians practice “general internal medicine” and are commonly referred to as “general internists.” General internists are equipped to handle the broad and comprehensive spectrum of illnesses that affect adults, and are recognized as experts in diagnosis, in treatment of chronic illness, and in health promotion and disease prevention—they are not limited to one type of medical problem or organ system. General internists are equipped to deal with whatever problem a patient brings—no matter how common or rare, or how simple or complex. They are specially trained to solve puzzling diagnostic problems and can handle severe chronic illnesses and situations where several different illnesses may strike at the same time. 

Some internists choose to take additional training to "subspecialize" in a more focused area of internal medicine. Although physicians who have completed additional training in a particular area of internal medicine are frequently referred to by their area of subspecialty focus (for example, those who subspecialize in diseases of the heart are usually called “cardiologists”), all share the same basic internal medicine training and like general internists are also considered “internists.” The training an internist receives to subspecialize in a particular medical area is both broad and deep, and qualifies them to manage very complex medical issues and perform advanced clinical procedures.