The symptoms of anal fistula are also the symptoms of anal fistula: 1. Pus flow is the main symptom of anal fistula, there is constant pus overflow from the external mouth and the perianal abscess rupture, there is more pus in the acute period and less pus in the chronic period, sometimes the external mouth is closed, there is local redness, swelling and pain, after the closed mouth is ruptured and pus flows out, the pain gradually disappears, the repeated episodes do not heal for a long time. 2. pain, pus is removed smoothly patients do not have pain, the external mouth is closed pus can not 3. itching, as the pus continuously overflows from the external mouth, it can stimulate the perianal skin causing perianal itching and anal eczema, etc.