Lack of bowel movement may be caused by under-eating, gastrointestinal insufficiency, intestinal obstruction and other factors. 1. Eating too little: when you eat too little, the content in the intestine is less, which is not enough to trigger the bowel reflex, and then you may not have bowel movements. 2. Insufficient gastrointestinal power: the intestinal tract needs to move to push the food to the anus, when the gastrointestinal power is insufficient, the food can’t stimulate the rectum and anus enough, which leads to the lack of bowel movement. 3. Intestinal obstruction: when the intestinal tract is obstructed, the intestinal contents at the upper end of the obstructed area cannot pass through the obstructed area smoothly, and there is not enough fecal matter accumulation in the colon, which may also lead to the situation of no bowel movement. When there is no bowel movement, you should consult a doctor in time, complete the relevant examinations under the guidance of the doctor, clarify the cause of the disease, and actively treat the disease.