What is an Internal Medicine Physician, or Internist?

Internal Medicine physicians are experts in complexity. They see every connection in the adult human body. Internal Medicine Physicians serve, and lead, in many diverse roles and settings. They are critical thinkers who thrive in uncertainty and excel in the most challenging and dynamic environments, and care for patients throughout their health care journey. Their expertise makes them vital to both patients and medical professionals.

Internal medicine physicians 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. They are especially well trained in the diagnosis of puzzling medical problems, in the ongoing care of chronic illnesses, and in caring for patients with more than one disease. Internal medicine physicians also specialize in health promotion and disease prevention.

Internal medicine physicians can be called "internists," "general internists," and "doctors of internal medicine." They are not, however, "interns," who are doctors in their first year of residency training.

Internal Medicine physicians routinely see patients with chronic conditions such as heart disease, hypertension, diabetes, obesity, and pulmonary disease. Often, other medical professionals call upon Internal Medicine Physicians for their ability to connect the dots, help solve problems, and identify solutions.

To become an internal medicine physician, a graduate of a four-year medical school must complete a residency in internal medicine, which usually lasts three years. Once general internal medicine residency training is complete, a physician may begin to practice internal medicine, or an internal medicine physician may then choose to subspecialize in a particular area of internal medicine, for example, cardiology or infectious diseases. Subspecialty training, called fellowship, calls for two to three years of additional training.

Most general internal medicine physicians provide care for their patients in an ambulatory setting (office or outpatient), and may also follow their patients when hospitalized (inpatient setting). Other internal medicine physicians are known as “hospitalists” and care for patients only in the hospital.

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.

Learn more about the unique leadership roles, career pathways and impact of internal medicine physicians. Learn more