Fistula is a chronic pus discharging sinus occurring in the vicinity of anal canal. It starts from within the anal canal. Pus is formed inside the anus and bursts out of anus. There is swelling around anus and it bursts out leaving a sinus. There are recurrent episodes of pus formation and sometimes it dries up with medicine and again collection of pus occurs. It is best treated by the use of Ksharsutra. The surgery is frustrating because chances of recurrence are fair after surgery. Ksharsutra delivers medicine at the beginning point to destroy infected focus and it also ensures slow cutting and healing. The chances of recurrence are nil after application of Ksharsutra.