The process in which the semi-solid or soft digested waste of food is expelled from the digestive tract as faeces is called defecation or egestion. Stool-like material is moved from the colon to the rectum by the contraction waves of the colon muscles or the process of peristalsis. A slippery mucous substance secreted from the colon wall acts as a lubricant to facilitate stool passage. When the bladder is full to a certain degree, pressure is created on its walls. It causes defecation reflex and urges to pass stool. Stool enters the anus under the pressure of the rectal wall and pelvic muscles. Stool is expelled through the anus by the peristalsis action of the anus. Two sphincter muscles located in the anus control the passage of stool. Pain, fear, temperature, physical or neurological complications affect the process of defecation.