The baby drank milk powder for four days without poop, may appear functional constipation, can be resolved through medication, dietary adjustments, if necessary, timely medical treatment. 1. medication: formula-fed babies can generally form a more regular stool, four days without stool, may be functional constipation, you can follow the doctor’s instructions to use lactulose and other laxatives to help defecate, if necessary, you can use the Kesler, lubricate the intestinal tract, stimulate the discharge of stools. 2. Adjust the diet: If you have added complementary foods for babies, you can eat appropriate fruits and fresh vegetables, such as bananas and spinach, which are rich in dietary fiber, can also promote intestinal peristalsis to a certain extent, to improve functional constipation. 3. Timely medical treatment: If the baby, in addition to the above symptoms, there are obvious abdominal pain, stop eating, blood in the stool, stop anal discharge and other manifestations, you need to consult a doctor in a timely manner. Therefore, if your baby has not had a bowel movement for a long time, it is recommended that you seek prompt medical attention and active treatment. The above medications should be used in accordance with medical advice.