Acute necrotizing small bowel colitis is commonly caused by the following reasons: hypoxia, infection, dietary factors and so on. 1. Hypoxia: When hypoxia occurs, the microcirculation of the intestinal wall will be impaired, and some of them are combined with DIC at the same time, so that the intestinal wall will be hypoxic, which induces necrotizing small bowel colitis. 2. Infections: for example, type C Pseudomonas aeruginosa infection, bacteria can produce toxins, and these bacterial toxins can lead to necrosis of intestinal mucosa. 3. Dietary: It may be associated with a defective diastase or, in the case of newborns, with high milk osmolality. After the occurrence of this disease, comprehensive treatment is needed, including anti-infection, nutritional support, surgical treatment and so on.