Poop, also known as faeces is 75% water, while the remaining 25% is dead bacteria and indigestible food, such as fibre which is used to help the transport of the faeces through the intestine.
In humans, defecation occurs, depending on the individual and the circumstances, from once every two or three days to several times in a day. Extensive hardening of the feces may cause prolonged interruption in the routine and is called constipation.
Human fecal matter varies significantly in appearance, depending on diet and health. Normally it is semi-solid, with a mucus coating. Its brown coloration comes from a combination of bile and bilirbun, which comes from dead red blood cells.
In newborn babies, fecal matter is initially yellow or green after the meconium. This coloration comes from the presence of bile alone. In time, as the body starts expelling bilirubin from dead red blood cells, it acquires its familiar brown appearance, unless the baby is breast feeding, in which case it remains soft, pale yellowish, and not completely malodorous until the baby begins to eat significant amounts of other food.
Throughout the life of an ordinary human, a person may experience many types of faeces. A green stool is from a rapid transit of feces through the intestines and a clay-like appearance to the faeces is the result of a lack of bilirubin.
Food may sometimes make an appearance in the faeces. Common undigested foods found in human faeces are seeds, nuts, corn and beans, mainly because of their high dietary fiber content. Beets may turn faeces different shades of red. Artificial food colouring in some processed foods such as highly colorful packaged breakfast cereals can also cause unusual faeces coloring if eaten in sufficient quantities.
Human faeces along with other animal faeces may be used as a fertilizer in the form of biosolids, manure and guano. Some animal faeces especially those of camels, bison and cattle are used as fuel when dried out.
