Senna leaves in water to drink, generally 3-4 hours or so can appear to have a bowel movement, but the specific time and personal constitution and senna dosage, there are individual differences. Senna belongs to the diarrhea class of drugs, its nature is cold, taste sweet and bitter, into the large intestine meridian, has the convenience of water, diarrhea and stagnation of the efficacy. Senna leaves into the intestinal tract to stimulate the intestinal wall, so that the feces quickly crowded, the effect is faster, mainly for the treatment of constipation and abdominal pain, edema and bloating, heat and stagnation. Secondly, there are antibacterial, detoxification, hemostatic effect. Constipation can be appropriate to take laxatives to assist in defecation, but it is not recommended to commonly used. Senna drinking water has a laxative effect, but can not be used as a treatment, long-term use will cause nerve dysfunction of the intestinal wall, caused by decreased intestinal tone instead of aggravating the symptoms of constipation, before taking attention to rule out intestinal obstruction and other serious intestinal diseases. If often constipated, it is recommended to drink more water, eat more vegetables and fruits, more exercise, to develop good bowel habits, if necessary, need to go to the gastroenterology department.