Defecation

Defecation (or defaecation) follows digestion and is the necessary biological process by which organisms eliminate a solid, semisolid, or liquid waste material known as feces (or faeces) from the digestive tract via the anus or cloaca. The act has a variety of names, ranging from the technical (e.g. bowel movement), to the common (like pooping or crapping), to the obscene (shitting), to the euphemistic ("doing number two", "dropping a deuce" or "taking a dump"), to the juvenile ("going poo-poo" or "making doo-doo"). The topic, usually avoided in polite company, forms the basis of scatological humor.

Humans expel feces with a frequency varying from a few times daily to a few times weekly.^[1] Waves of muscular contraction (known as peristalsis) in the walls of the colon move fecal matter through the digestive tract towards the rectum. Flatus may also be expulsed. Undigested food may also be expelled within the feces, in a process called egestion. When birds defecate, they also expel urine and urates in the same mass, whereas other animals may also simultaneously urinate during defecation, but the processes are spatially separated. Defecation may also accompany childbirth and death. Babies defecate a unique substance called meconium prior to eating external foods.

There are a number of medical conditions associated with defecation, such as diarrhea and constipation, some of which can be serious. A simpler and more mundane concern is the maintenance of anal hygiene, which usually calls for cleaning the area shortly after defecation. The feces expelled can carry diseases, most often through the contamination of food. E. coli is a particular concern.

Before toilet training, human feces are most often collected into a diaper. Thereafter, in many societies people commonly defecate into a toilet. A Western-style flush toilet requires a sitting position, as compared with a squat toilet. However, open defecation, the practice of defecating outside without using a toilet of any kind, is still widespread in some developing countries;^[2] some people in those countries defecate into the ocean. Well-developed countries use sewage treatment plants or on-site treatment for blackwater.