Ileus causes stomach bloating and pain due to a buildup of gas and fluid, as well as nausea, vomiting, severe constipation, lack of appetite, and cramping. It is possible that people will pass watery stools. In fact, this is normal when you have ileus; the only thing that isn't normal is if your stool is black or tar-like. People who have ileus may not appear to have bowel movements for several days. If you are having problems passing stool or urine, see your doctor immediately.