Diarrhea Diarrhea means having loose, watery, or more frequent stools than usual. It is common and often short-term, especially when caused by a stomach virus, food irritation, or something you ate. Many cases improve with fluids, rest, and supportive care. However, diarrhea can sometimes lead to dehydration or may be a sign of infection, medication side effects, food intolerance, inflammatory bowel disease, or another medical condition. Knowing what to watch for can help you