Intestinal Obstruction as Cause of Acute Abdomen Intestinal obstruction is one of the most common causes of acute abdomen. Successful therapy depends on the correct diagnostic assessment without delay. ‘Ileus disease’ describes the development of endogenous alterations generating critical illness including life-threatening decompensation of vital organ systems. The most common causes of small-bowel obstruction are adhesions, whereas obstructing colorectal carcinoma is most frequently the reason for large-bowel obstruction. Vascular intestinal obstruction has to be treated by emergency surgery due to complicating ischemia of the bowel wall. In the postoperative period, the differentiation between prolonged ileus, mechanical and paralytic intestinal obstruction may be difficult. Due to heterogeneous patient populations and variability of causes, therapeutic strategies are not standardized and, therefore, therapy of intestinal obstruction is a surgical challenge in many cases.