Clinical practice has observed that more women than men suffer from constipation, and foreign survey data from Europe and the United States show that women are twice as likely to suffer from constipation as male patients. So why does this happen? This is mainly related to the instinctive bladder-anal reflex of the human body. The nerves of the urethral and anal sphincters are derived from the same sympathetic, parasympathetic and somatic nerves, which means that the bladder and anus are innervated by common vegetative and somatic nerves. When urinating, the electrical activity of the external sphincter is fully inhibited, while the electrical activity of the internal sphincter increases. At this time, the internal sphincter is in a state of contraction in order to prevent the overflow of stool, which is not under conscious control and is a normal physiological reflex. In order to prevent the discharge of feces in the rectum, through the bladder-rectum reflex, the tension of the internal sphincter is higher than that of men, plus women have a short urethra and more chances of urinary tract infections, which often occur more frequently and more easily stimulate the spasm of the internal sphincter. At this time, influenced by the reflex of the internal rectal sphincter, the internal sphincter spasm is rectal expansion, fecal storage increases, water is transitory absorption, thus the occurrence of constipation.