The anus is often moist and smelly, the consideration is anal fistula, anal fistula is a channel formed between the rectum and perianal skin, stool will flow out of the channel, so the perianal area will be moist, itchy, and sometimes there will be a foul smell, pus or feces on the underwear. The treatment of anal fistula is relatively small, the effect of drug treatment is very poor, consider surgical treatment, there are many surgical methods, such as anal fistula excision, anal fistula incision, anal fistula hanging line, surgical methods of different healing is also different, according to the operation of the specific situation to decide on the specific surgical methods, generally come to diagnose the fistula, it is recommended that the positive surgery, because the longer the delay, the longer the delay, it may be simple simple fistula, dragged into a Complexity, multi-channel anal fistula, so that anal fistula surgery is not good, and easy to recur.