Anal fistula is usually formed by the normal structure of the anal canal sinus inflammation, spread to the surrounding soft tissues and infection. There are several normal structures in the anal canal sinus, in frequent diarrhea, constipation or stool with fecal debris or pathogenic bacteria will cause edema and inflammation of the sinus, the inflammation can spread to the surrounding soft tissues and infection, causing perianal abscess. In the abscess burst after the discharge of pus, but the abscess at the inflammation of the tissue still exists, after a long time to form an inflammatory pipe, the mouth of the two ends of the pipe are known as the inner mouth and the outer mouth, so that the formation of anal fistula this kind of disease. To eradicate anal fistula must be surgically removed through the corresponding fistula and internal and external orifices, if the treatment is not complete, it is easy to recur. Once found anal fistula, it is recommended to go to the hospital in a timely manner to check, give diagnosis and treatment, anal fistula will not be self-healing, only more and more damage to the perianal tissue, affecting the normal life.