1. The anus is in a special position, easily squeezed by the muscles of the buttocks on both sides and poorly exposed; 2. Daily defecation is required, which is easily stimulated and contaminated; 3. The anal surgery trauma is mostly open trauma, mostly located in the anus, which is prone to poor drainage, granulation, edema, bleeding, delayed healing, and even trauma infection, resulting in recurrence of traumatic lesions. It is usually not easy to heal properly without changing the medication. At the same time, anal surgery often has special circumstances such as leather straps, internal hemorrhoid ligature lines, and counter-oral drainage, which need to be observed and dealt with promptly when changing medication. In addition, the change of medication in the anal area is also an important treatment process, so the change of medication after anorectal surgery is particularly important. Drug changes are usually performed after emptying the stool and cleaning the anus, and are usually performed once a day in the morning or evening after defecation.