The anal canal actually secretes fluid under normal circumstances, which is a physiological reaction, but if there is a yellowish and smelly situation mentioned by the patient, the following reasons are mainly considered: 1. the relaxation of the anal sphincter, the patient’s local secretion will be accompanied by the discharge of feces, so the yellowish and smelly situation is due to the natural state of feces, which is easy to understand. 2. local inflammatory reaction, rectal inflammation or with some other inflammatory reaction, easily causing changes in the nature of the secretion. 3. cause this serious clinical reaction, which is needed for surgical treatment.