Diarrhea involves having bowel movements that are watery and loose at least three times in a day. It may also cause a sense of urgency, cramps and stomach upset. Diarrhea can be brought on by bacteria, parasites, disorders of the gastrointestinal tract, medication or food intolerances. In most cases, diarrhea is not a long-lasting or serious condition. However, if it lingers for more than three days, is accompanied by a fever or severe abdominal pain or you notice blood in your stool, it is important to visit your doctor for an examination.