Intestinal transplantation is a specialized area within transplant medicine and surgery focused on the surgical replacement of a diseased or absent small intestine, often combined with other abdominal organs. As a research concept, it encompasses the investigation of complex immunological challenges including rejection and graft-versus-host disease, the development and optimization of surgical techniques and immunosuppressive regimens, and the study of long-term patient and graft outcomes for individuals with irreversible intestinal failure.