The internal opening is usually clean for about 3 weeks after anal fistula surgery. After having anal fistula surgery, the wound will gradually heal in about a week. Postoperative care is very critical, must keep the local clean and dry, wash the anus with warm water every day, change the medication on time, and take anti-inflammatory drugs according to the doctor’s instructions, such as cefixime, amoxicillin, etc., can also be injected intravenously with cefepime, levofloxacin, etc., to avoid postoperative infection, promote wound healing, and the inner mouth is clean in about 3 weeks. Postoperative diet should be light, easy to digest, the first 2 days to liquid food, 2 days later you can eat semi-liquid food, eat more fresh vegetables and fruits and high protein food, do not eat spicy or stimulating food, is conducive to the smooth flow of stool and wound healing. If the inner mouth is still not clean about 3 weeks after the anal fistula surgery, it is recommended to go to the hospital in time for diagnosis and treatment by professional doctors.