Loose, watery, or frequent bowel movements that last more than two days can be caused by infections, food allergies, medications, inflammatory bowel disease, and more. It may be accompanied by cramps, stomach pain, bloating, nausea, fever, or blood in the stool. Persistent diarrhea can be serious and may be a symptom of an underlying health problem such as celiac disease, IBS, inflammatory bowel disease (IBD), small intestinal or bacterial overgrowth (SIBO) to name a few.