Internal medicine is the study of all diseases in the human body.

The Department of Internal Medicine at Yonsei University College of Medicine divides diseases into the 11 divisions of infection, endocrine, rheumatism, digestive system, kidney, heart, allergy, tumor, integration, blood, respiratory system, and old age, and offers classes accordingly.

The department is actively engaged in research through the Institute of Gastroentology, the Institute of Chest Diseases, the Institute of Allergy, the Institute of Endocrinology and the Yonsei Cardiovascular Research Institute, and also plays a significant role in the Institute for Cancer Research.