It is not normal for babies to have a bowel movement once every three or four days after taking formula. The baby more than three days no stool belongs to constipation, divided into functional constipation and organic constipation, need to find the cause according to the baby’s specific situation to give symptomatic treatment. 1. Functional constipation, mostly due to factors such as milk powder, drinking water and other factors caused by the slowing of gastrointestinal peristalsis, resulting in abnormal bowel movements. The constipation can be improved by changing the milk powder and increasing the water intake of the baby. 2. Organic constipation, such as congenital megacolon, intestinal stenosis and other diseases can lead to the baby defecation difficulties, constipation, the need to go to the hospital surgery in time to improve the abdominal ultrasound and other related examinations, according to the condition of the timely surgery and other symptomatic treatment. There are a variety of possible causes for a baby to eat milk powder once every three or four days, you should seek medical advice and treatment under the guidance of a doctor.