Diarrhea occurs when your child's bowel movement pattern changes to loose, watery stools that occur more frequently than usual. If a child produces loose, very watery stools more than 6 to 8 times a day, he or she likely has diarrhea.

It is sometimes difficult to tell when a young baby has mild diarrhea, because an infant's stools are normally soft and a little runny. If your young baby has an increase in stool frequency and an unusually high amount of liquid in the stool, he or she may have diarrhea.