Digestive fistulas are usually located in the stomach, intestines, and colon. They are often a complication of a gastrointestinal illness as in case of the perforation of a duodenal or gastric ulcer, for example, a problem following surgery, or rarely trauma. The contents of the digestive tract are then poured into another organ, digestive or not, in the abdominal cavity, sometimes directly to the skin. In the case of an overflow of feces into the bladder through a urodigestive fistula, feces may be passed in the urine. Care for this kind of fistula involves surgery.