Most cases of diarrhea (runny or watery bowel movements) are caused by gastrointestinal (GI) infections. Diarrhea usually is not a sign of a serious illness, but it can cause kids to lose fluids, salts, and minerals. If your child has diarrhea, it's important to make sure fluids and nutrients are replaced.
Make sure kids wash their hands well and often to avoid getting infected with germs that can cause diarrhea. Wash fruits and vegetables thoroughly before eating, and refrigerate meats as soon as possible after buying them and cook them until they're no longer pink.