Dilatation of the small intestine is an important manifestation of malabsorption syndrome, mostly in the jejunum, especially in the lower and middle part of the jejunum, and sometimes can cause dilatation of the entire small intestine, including the duodenum. The degree of small bowel dilatation is related to the severity of the disease, and the cause of dilatation is low tone of the small bowel. It is believed that a small bowel diameter greater than 31 mm can be considered dilated, and the bowel diameter can be two to three times the normal size when it is significantly dilated. Inflation of the small intestine can be mild or severe, while the majority of colonic inflation is more pronounced, often manifesting as peritoneal inflation of the entire colon frame. The distribution of small bowel inflation is mostly in the middle abdomen within the colonic frame, and when the dilatation is severe, the intestinal loops are in the form of continuous tubes; when the dilatation is mild, it appears as separated inflatable intestinal tubes. Diagnosis of dilated and inflated small intestine due to intestinal obstruction: (1) Abdominal pain: paroxysmal colic. For jejunal or upper ileal obstruction, there is an episode every 3-5 minutes, and for terminal ileal or large bowel obstruction, there is an episode every 6-9 minutes, with pain relief between episodes and hyperactive bowel sounds during colic. The bowel sounds are high pitched. Sometimes the sound of air over water can be heard. Paralytic intestinal obstruction may have no abdominal pain, high small bowel obstruction may have less severe colic, and intermediate or low bowel obstruction may have typically severe colic, located around the umbilicus or poorly localized. Each colic may last from a few seconds to several minutes. If the paroxysmal colic turns into persistent abdominal pain, the development of strangulated intestinal obstruction should be considered. (2) Vomiting: After the obstruction, the retrograde peristalsis of the intestinal tube causes the patient to vomit. The vomit starts with gastric contents and later with intestinal contents. High small bowel obstruction is not severe in colic, but vomiting is frequent. In middle or distal small intestine obstruction, vomiting appears later, and in low small intestine obstruction, vomit is sometimes “feculent vomitting” due to the retention of intestinal contents, bacterial overgrowth and decomposition of intestinal contents. (3) Abdominal distension: Mostly occurs in the late stage, high small bowel obstruction is not as obvious as low one, and colonic obstruction rarely occurs due to the presence of ileocecal valve, and the obstruction is often closed loop, so the abdominal distension is obvious. In strangulated intestinal obstruction, the abdomen is asymmetrically distended and the enlarged intestinal loops can be felt. (4) Cessation of defecation and bowel movement: Patients with intestinal obstruction usually stop defecating and defecating from the anus. However, mesenteric vascular embolism and intussusception can pass loose stool or bloody mucus. Patients with colonic tumors, diverticula or gallstone obstruction also often have black stools.