A three-year-old baby pooping once every three days may be caused by physiological factors, which is normal, or it may be caused by the child’s poor appetite and eating less, or it may be caused by the child’s constipation, which is not normal. 1. Physiological factors: three-year-old baby three days to pull a stool, if the color and character of the stool are normal, there is no stool dryness and so on, and the child did not appear to cry, irritability, depression and other manifestations of play, play everything is normal, then it may be a normal phenomenon. 2. poor appetite: if the child’s recent poor appetite, eat less, then it may also lead to three-year-old baby appeared three days a stool symptoms, this situation need to find out why the baby recently eat less, take the baby to check whether there is a zinc deficiency and so on. 3. constipation: if the baby’s recent diet is based on meat and other foods, the lack of dietary fiber-rich vegetables, fruits and other foods, may lead to the baby constipation, so that the three-year-old baby appeared to poop once every three days. Parents need to give the child to change the diet, as well as oral baohe oral liquid and other digestive aids, method of Lactobacillus acidophilus regulation and other sections of the intestinal flora, to help alleviate the symptoms. After eliminating physiological factors, if the symptoms of three-year-old baby pooping once every three days continue to be unrelieved, it is recommended to consult a doctor in time. The above drugs need to be used in accordance with medical advice.