Gastrointestinal bleeding (GIB) can occur as a complicating issue in the postoperative course after visceral surgery. It can be of varying clinical extent ranging from mild anemia to fatal hemorrhagic shock. Symptomatic manifestations of a GIB are hematemesis, melena and hematochezia. The GIB are fundamentally differentiated into upper and lower GIB. While upper GIB is defined as the occurrence of endoluminal hemorrhage above the ligament of Treitz, correspondingly the definition of lower GIB is intraluminal bleeding distal to the duodenojejunal flexure. Knowledge of their procedure-related incidence during the postoperative course enables a better assessment of the necessary intervention.