After sigmoid resection, fecal matter is usually not drained from the drain; if this occurs, consider the possibility of an anastomotic fistula. After sigmoid resection you can defecate through the original anus, and if the patient is left with a colostomy, you will usually defecate through the colostomy. However, fecal water is usually not discharged through the drainage tube. If fecal water is discharged through the drainage tube, an anastomotic fistula may have occurred, allowing the intestinal contents to be discharged through the drainage tube. At this time, we should pay attention to keep the drainage tube open, do not make the drainage tube bent, folded, etc., to avoid the exudate can not drain out, the phenomenon of infection. Most fistulas can grow naturally, and attention should be paid to nutritional supplementation, especially protein supplementation. It is recommended that patients maintain a good state of mind, light and nutritious diet, do not stay up all night, to promote the recovery of the body. Patients are advised to notify the doctor in time when abnormal changes occur in the nature and amount of drainage fluid, and to treat accordingly to avoid aggravation of the condition.