One year old babies eat and poop may be caused by indigestion, intestinal inflammation, milk protein allergy and other reasons. 1. Indigestion: If the child has gastrointestinal discomfort, the symptoms of diarrhea will appear. At this time, we should pay attention to the warmth of the abdomen, eat small meals, eat more rice flour, and eat less high protein food. 2. Intestinal inflammation: Intestinal inflammation is caused by rotavirus infection, norovirus infection, bacterial infection and so on, which will lead to indigestion and then the symptom of diarrhea after eating. 3. Milk protein allergy: If the child has diarrhea for a long time, it may be milk powder allergy, which can be relieved by changing milk powder and adjusting diet. If a one year old baby has the symptom of diarrhea after eating and not relieved by himself, he should go to the hospital as soon as possible to avoid aggravation of the condition.