The first thing you need to do is to change the medication after anal fistula surgery in several steps, including cleaning the wound and thoroughly disinfecting it, as follows: 1. The first thing you need to do is to use the same disinfection solution as you did for the first time. The change of medication for anal fistula is usually done after defecation to prevent the patient from defecating again after the change of medication and affecting the healing of the surgical incision. The change of medication is an important treatment for post-operative patients, as it can accelerate the healing of the surgical incision, reduce post-operative complications, and prevent post-operative pseudo-healing.