Internal medicine is a primary division of healthcare dealing with the prevention, diagnosis, and treatment of adult diseases. Generally, internal medicine provides primary care to men and women age 18 and up. These providers seek to provide physical exams, screenings, and vaccinations that help patients stay healthy and maintain a high quality of life. Physicians working in internal medicine are often called internists. Internists often see patients for prevention and maintenance of good health such as physical exams or vaccinations. You may also seek the care of an internist for common issues such as cold, flu or for more chronic adult illnesses like asthma, diabetes, hypertension, etc.