Diarrhea An infection, trouble digesting certain foods, or too much fruit juice are among the causes. If your child gets it, keep her at home and hydrated. If she's on solids, avoid high-fiber and greasy foods. Call the doctor if she isn't better in 24 hours, is under 6 months old, or has other symptoms, such as a fever of 101 or higher, vomiting, peeing less than usual, fast heart rate, bloody or black stool, or belly pain. Fever Call the...