1. Definition and Symptoms of Diarrhea Diarrhea refers to an increase in the number of bowel movements per day, an increase in the amount of stool, thin or watery stool, and is accompanied by uncomfortable symptoms such as frequent defecation, abdominal distension, and abdominal pain. For one-year-old babies, diarrhea may cause problems such as loss of appetite and weight loss. 2. Causes of diarrhea in one-year-old babies 1. Infectious factors: including