Anal fistula is short for anorectal fistula, which is a lesion that occurs as a sequela to the ulceration or incision and drainage of an abscess around the anorectum. It refers to a granulomatous tube around the anus and is an inflammatory disease of the soft tissues of the skin. This inflammatory sinus tract of the rectal-anal canal and perianal soft tissues interconnecting with each other is lined with inflammatory granulation tissue or the lumen is filled with purulent and putrid tissue, and a small amount of secretion flows from the fistula. In layman’s terms, the state of anal fistula is like a “tunnel” between the inner wall of the rectum and the perianal skin, which is not a good thing, because from time to time there are secretions seeping out of the openings in the skin. What are the symptoms and harms of anal fistula: 1, pain: when the fistula is smooth without inflammation, usually no pain, only a slight sense of localized swelling in the anus, walking can be aggravated, if the outer mouth is closed, the fistula deposits pus, or feces into the fistula, the pain will be aggravated or aggravated pain in defecation, and internal blind fistula is often felt in the lower part of the rectum and the anus, burning discomfort, and aggravation of pain in defecation. This will affect the work and study, over time can make the body weak and thin, mental fatigue, decline in resistance to disease, anemia, attacks are more frequent. 2, itching: the anal skin due to pus and other discharges stimulation, often feel itchy skin. 3, defecation: most commonly seen in hoof iron fistula, because the fistula around the anal canal, the formation of semi-circular fibrous ring, thus affecting the anal diastasis, may appear defecation. 4, pus: pus is its main symptom. Generally speaking, the newly generated fistula pus more, pus thick, yellow, odor; fistula for a long time pus is relatively small, or sometimes, dilute as water; if the amount of pus increases, it means that the new fistula generation. Fistula will sometimes be temporarily closed, no discharge of pus, resulting in localized swelling and pain, temperature rise, later closed fistula rupture, and discharge of pus, but also from the fistula discharge of gas or feces. 5, hard knot or scar: due to the repeated stimulation of the fistula wall and fistula, so that the fibrous tissue proliferation, the formation of tough connective tissue in the wall and fistula, often manifested as a fistula around the skin discoloration, epidermal detachment, depression and deformation, and touching the stripes of hard knots leading to the anus. 6, systemic symptoms: most of the systemic symptoms, when the anal fistula invasion range is larger and deeper or more branches, repeated inflammatory infections, will lead to wasting, anemia, constipation, defecation difficulties and other systemic symptoms. 7, many repeated episodes: the pus can penetrate the wall of the tube and spread along the sphincter space to form multiple, complex anal fistula, not only to the treatment of difficulties, but also affect the normal physiological function of the anus. The multiple anal fistula, can form rectovaginal fistula, rectal urethral fistula and rectal bladder fistula, endangering the surrounding organs, and anal fistula has a tendency to malignant. 8, the impact on sexual life: anal fistula patients secretion of pus can affect the quality of sexual life, especially female anal fistula patients, anal fistula secretion during sex into the vagina can cause vaginal infection, and then produce more serious gynecological diseases. The fistula should be treated in time to prevent the deterioration of the condition. It is best to use surgical treatment, the principle of surgical treatment is to cut all the fistula, if necessary, the scar tissue around the fistula at the same time excision, so that the wound from the base upward gradual healing.