Two months after the anal fistula surgery are still cavity may be ulcerative colitis, leucosis, tuberculosis, anal fistula recurrence and other causes. Patients should immediately go to the hospital for treatment. 1. Ulcerative colitis: ulcerative colitis is a chronic non-specific inflammation of the colon and rectum. It is usually caused by genetic, environmental and immune factors. Patients may have symptoms such as abdominal pain, blood in the stool and constipation. 2. Leukoaraiosis: Leukoaraiosis is a recurring chronic inflammatory disease, which may be caused by fungal and bacterial infections, etc. Patients usually have symptoms such as mouth ulcers and vulvar ulcers. 3. Tuberculosis: tuberculosis is an infectious disease caused by Mycobacterium tuberculosis infection, which may be caused by patients living in overcrowding, malnutrition and other reasons, patients usually have symptoms such as fatigue, cough, fever. 4. Anal fistula recurrence: anal fistula recurrence refers to the recurrence of anal fistula caused by the formation of an external opening in the perianal skin, which may be caused by the internal opening in the operation is not completely removed or secondary infection, and so on, and the patient may experience redness, swelling, heat and other symptoms in the perianal area. Patients should immediately go to the hospital, improve the examination, clarify the cause of the disease, and early treatment under the guidance of the doctor.