Bowel fluid overflow may be caused by anal sphincter relaxation, anal fistula and other causes. 1. Anal sphincter relaxation: it means that the anorectal ring is not enough to control the bowel movement, which is mostly seen in the elderly and frail patients. Secondly, if the patient undergoes anorectal surgery, the anorectal ring may be damaged during the surgery or the spine may be damaged leading to nerve damage, thus causing the anal sphincter to relax. Typical symptoms of anal sphincter relaxation are fecal incontinence and overflow of intestinal fluid. 2. anal fistula: because the fistula directly from the rectum into the body surface, not through the anus, part of the intestinal fluid may be discharged through the fistula, usually manifested as intestinal fluid overflow. There are many other reasons for the overflow of intestinal fluid, it is recommended that patients seek medical attention in a timely manner to clarify the cause of the disease and standardized treatment as prescribed by the doctor.