Some patients with anal fistulas are treated surgically and the wounds do not heal for a long time with constant pus, which is difficult to heal and healing is very unsatisfactory. The main reasons for the difficulty in healing the post-operative wounds of anal fistula patients are the following 1, the surgery did not accurately find the inner mouth, or the treatment of the inner mouth is not correct, resulting in a false inner mouth; or even if the inner mouth is accurately found, but not thoroughly remove the infected anal sinus, the anal glands and the primary lesions of the internal sphincter, can also lead to poor healing. 2, rush surgery when the sinus tract has not yet formed, so that the inflammation spreads, forming new sinus tracts and pus cavities and affecting healing. 3, due to fistula bending, intraoperative fistula caused by false fistula or fistula was residual, or fistula necrotic tissue within the scratch is not clean, resulting in difficult healing and recurrence of the traumatic mouth. 4.A gap or dead space is left in the wound suture, or the suture tension is too large. 5.Foreign objects, such as threads, cotton wool, etc., are left in the wound opening and are buried by the surrounding granulation tissue, which affects the normal growth and healing of the wound opening. 6. The patient is excessively weak or has chronic diseases such as diabetes, tuberculosis, leukemia or anemia, which makes the wound difficult to heal for a long time.