Three months baby three days without defecation may be a normal physiological phenomenon, but it may also be caused by pathological factors, such as constipation, at this time belongs to the abnormal situation. 1. Physiological factors: three-month-old babies, the frequency of defecation will decline, there may be three days without defecation. As long as the baby’s mental state is good, diet, sleep and other normal, usually is a normal physiological phenomenon. 2. Pathological factors: If the baby’s long-term food is too little resulting in malnutrition, so that the abdominal muscles, intestinal muscles, thin, lack of tension, peristaltic weakness, will lead to stubborn constipation. Or due to life and defecation irregularity, resulting in the formation of defecation reflex weakened or not formed, at this time there will also be constipation, this belongs to the abnormal phenomenon. If a three-month-old baby has not had a bowel movement for more than five days, it is recommended that parents should take their babies to a doctor in time to do the relevant examinations under the guidance of the doctor, in order to clarify the cause of the disease, and symptomatic treatment.