What is happening in babies? Diarrhea in babies refers to an increase in the number of defecation times in babies, and the stool is thin or watery. In severe cases, it is also accompanied by symptoms of dehydration. Diarrhea in a five-month-old baby usually causes parents concern and worry. The following is a detailed explanation of the causes and treatment methods of baby diarrhea from several aspects. Reason analysis 1. Dietary reasons: The baby is five months old and may cause diarrhea when he first starts to try complementary foods. complementary food