A doctor who specializes in general internal medicine primarily works to manage complex diseases or conditions that may impact multiple systems within or areas of the body. Internists are physicians who have specialized in the detection, prevention, and treatment of adult illnesses. Internal doctors are often brought in to diagnose complicated conditions with no clear and obvious cause. An internal medicine specialist can provide comprehensive care and support for patients with an array of conditions that may be co-occurring. When you require a diagnosis for an unknown illness or chronic disease, an internal medicine specialist will have the tools and expertise necessary to narrow the scope of your testing and provide you with a precise diagnosis while also helping you decide on a course of treatment.