The baby’s poop after eating breast milk may be caused by imperfect development of the gastrointestinal tract, gastroenteritis and so on. 1. Gastrointestinal tract imperfect development: due to the baby’s age, the gastrointestinal tract development is imperfect, digestive function will be relatively poor, which makes the intestinal peristalsis is relatively fast, so the baby will eat breast milk may be poop. And this situation is also called gastrocolic reflex, that is to say, the baby in the stomach after eating caused by the stomach filling reflexively caused by the colon to increase the movement of the phenomenon of high frequency of defecation. 2. gastroenteritis: baby with gastroenteritis can also make the baby eat breast milk on the poop, this is because gastroenteritis will make the baby’s intestines and stomach become fragile, but also may make the baby indigestion, resulting in baby diarrhea. In addition to the above factors, do not rule out other factors caused by the patient is recommended to go to the hospital as soon as possible to check by the doctor to clarify the cause of the disease, give targeted treatment.