1. What is diarrhea? Diarrhea refers to increased frequency of bowel movements, decreased stool volume, thin or watery texture, and symptoms associated with diarrhea. Since the intestinal immunity of a one and a half year old baby is not yet complete, he or she is easily infected with bacteria, viruses, etc., causing diarrhea. 2. What are the causes of diarrhea? 1. Food allergy or intolerance; 2. Infectious diarrhea: bacteria, viruses, etc.; 3. Digestive tract