Mannitol can treat constipation, but it does not treat bowel obstruction constipation. Mannitol is an osmotic medication that works differently when used in different ways. Intravenous drip can treat cerebral edema; by oral, can raise the osmotic pressure in the intestinal tract, and then increase the water in the intestinal tract, then can increase the fecal matter, thinning, can be better discharged from the body. For intestinal obstruction constipation, oral mannitol is unable to achieve the effect of constipation treatment, patients need to solve the obstruction of the intestinal tract, after the constipation can be relieved. Mannitol can’t be taken in large quantities for a long time, which may cause bacterial imbalance and aggravate the constipation. Constipation patients need to identify the cause of the problem and then follow the doctor’s instructions. The use of mannitol should be under the guidance of a medical professional.