Feces

# Overview
Feces, faeces, or fces (see spelling differences) is a waste product from an animal's digestive tract expelled through the anus (or cloaca) during defecation. The word faeces is the plural of the Latin word fx meaning "dregs". There is no singular form in the English language, making it a plurale tantum. 

# Etymology
Due to the nature of feces, several synonyms have developed.  Of these, some are generally used as profanity (such as shit and crap) while others have been deemed inoffensive (such as poo, poop, and dookie).  Other terms (such as dung) are normally used for animal feces rather than human feces.

# Ecology
After an animal has digested eaten material, the remains of it is excreted from its body as waste. Though it is lower in energy than the food it came from, feces may still contain a large amount of energy, often 50% of that of the original food. This means that of all food eaten, a significant amount of energy remains for the decomposers of ecosystems. Many organisms feed on feces, from bacteria to fungi to insects such as dung beetles, which can sense odors from long distances. Some may specialize in feces, while others may eat other foods as well. Feces serve not only as a basic food, but also a supplement to the usual diet of some animals. This is known as coprophagia, and occurs in various animal species such as young elephants eating their mother's feces to gain essential gut flora, or by other animals such as monkeys.
Feces are also an important as a signal. Kestrels for instance are able to detect the feces of their prey (which reflect ultraviolet), allowing them to identify areas where there are large numbers of voles, for example. This adaptation is essential in prey detection, as voles are expert at hiding from such predators. Some caterpillars even shoot their feces away from themselves in an explosive burst, helping them to avoid predators taking advantage of the olfactory signal it creates. In a non-predatory example, dominant wildebeest bulls defend territories marked with feces and pheromones produced by scent glands.
Seeds may also be found in feces. Animals which eat fruit are known as frugivores. The advantage in having fruit for a plant is that animals will eat the fruit and unknowingly disperse the seed in doing so. This mode of seed dispersal is highly successful, as seeds dispersed around the base of a plant are unlikely to succeed and are often subject to heavy predation. Provided the seed can withstand the pathway through the digestive system, it is not only likely to be far away from the parent plant, but is even provided with its own fertilizer.
Organisms which subsist on dead organic matter or detritus are known as detritivores, and play an important role in ecosystems by recycling organic matter back into a simpler form which plants and other autotrophs may once again absorb. This cycling of matter is known as the biogeochemical cycle. To maintain nutrients in soil it is therefore important that feces return to the area from which they came, which is not always the case in human society where food may be transported from rural areas to urban populations and then feces disposed of into a river or sea.

# Human feces
In humans, defecation may occur (depending on the individual and the circumstances) from once every two or three days  to several times a day. 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 semisolid, with a mucus coating. Its brown coloration comes from a combination of bile and bilirubin, which comes from dead red blood cells.
In newborn babies, fecal matter is initially yellow/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-unpleasantly scented until the baby begins to eat significant amounts of other food.
Throughout the life of an ordinary human, one may experience many types of feces. A "green" stool is from rapid transit of feces through the intestines (or the consumption of certain blue or green food dyes in quantity), and "clay-like" appearance to the feces is the result of a lack of bilirubin.
Bile overload is very rare, and not a health threat. Problems as simple as serious diarrhea can cause blood in one's stool.  Black stools caused by blood usually indicate a problem in the intestines (the black is digested blood), whereas red streaks of blood in stool are usually caused by bleeding in the rectum or anus.
Food may sometimes make an appearance in the feces. Common undigested foods found in human feces are seeds, nuts, corn and beans, mainly because of their high dietary fiber content. Artificial food coloring in some processed foods such as highly colorful packaged breakfast cereals can also cause unusual feces coloring if eaten in sufficient quantities.

## Differential Diagnosis of Causes of Feces Consistency

### Slimy
- Allergic diarrhea
- Amebic dysentery
- Chronic enterocolitis
- Colitis mucosa
- Gastroenteritis
- Pellagra

### Thin
- Constipation
- Rectal carcinoma

### Watery
- Acute gastroenteritis
- Carcinoid syndrome
- Cholera
- Intoxication

## Differential Diagnosis of Causes of Feces Color
Stool color can provide insight into the pathophysiologic basis of disease.

### Black Stool
- Melena, often the source is the upper GI tract as acid contents cause the stool to turn black. associated with acharacteristic foul smell. BUN will often be increased due to absorption of nitrogenous products in the upper GI tract.

### Bright Red
- Lower GI bleed
- Hemorrhoids

### Light Grey
- After radiocontrast use
- Bile duct occlusion
- Fatty stool
- Viral Hepatitis

## Personal hygiene
All cultures practice some form of personal cleansing after expelling feces.
- In Western society, the use of toilet paper is widespread.
- Other paper products were also historically used (before the advent of flush toilets).
- Before paper was cheap to produce, a "toilet rag" made of cloth was used, with a separate rag assigned to each family member.
- Several companies market toilet tissue or wipes for babies and campers.
- In some European countries, the use of a bidet for additional cleaning is common.
- In South Asia, showers are provided for use in toilets.
- In Islam, washing is prescribed by ritual cleansing with water, of which washing of the anus is part of the ablutions. The "act" of passing toilet, in Islam, requires ritual cleansing with water using the left hand. As religion is often practiced by widely differing cultural groups, Islamic tradition involves washing of the hands using soap and water after ablutions after using the toilet, to using of tissue paper to dry-off hands and other "wet" parts of the body to showers after each toilet use. In many Muslim countries, piped water is supplied inside toilets for both bathing and washing in addition to flushing of faecal matter. Such toilets are also common in Greece, Spain and parts of Eastern Europe.
- In India, the anus is also washed with water using the left hand. As with all such practices, hand washing after use of the toilet has become a very important public health issue.
- In England, there was historically much fascination with the act of going to the toilet, with royals appointing lesser mortals to assist with the removal of faeces and cleansing of the body parts using towels. The Indian toilet was adapted as the WC or water closet and widely deployed in England during the reign of Queen Victoria. London was the stage for several instances of food poisoning resulting from workers handling food after using the toilet. Cleansing of the anus was an arbitrary practice left to personal choice and facility available.
- In Ancient Rome, a communal sponge was used, which was then rinsed in a bucket of salt water.
- In Japan, flat sticks were used in ancient times, being replaced by toilet paper as the country became more "westernized." Toilets that include built-in bidets have now become widely popular in private homes.

## Bristol Stool Scale
Consistency and shape of stools may be classified medically according to the Bristol Stool Scale.
Pica, a disorder where non-food items are eaten, can cause unusual stool. Intestinal parasites and their ova (eggs) can sometimes be visible to the naked eye.

# Odor
The distinctive odor of feces is due to bacterial action. Gut flora produce compounds such as indole, skatole, and thiols (sulfur-containing compounds), as well as the inorganic gas hydrogen sulfide. These are the same compounds that are responsible for the odor of flatulence.  Consumption of foods with spices may result in the spices being undigested and adding to the odor of feces.  Certain commercial products exist that claim to reduce the odor of feces.  The perceived bad odor of feces has been hypothesized to be a deterrent for humans, as consumption or touching it may result in sickness or infection.  Of course, human perception of the odor is a subjective matter; an animal that eats feces may be attracted to its odor.

# Pets
Pets can be trained to use litter boxes or wait to be let out via several methods, such as crate training for dogs. Several companies market carpet cleaning products aimed at pet owners. However pet feces can be cleaned with just dishwashing detergent or liquid soap.  

# Uses
The feces of animals is often used as fertilizer; see manure.
Some animal feces, especially those of the camel, bison and cow, is used as fuel when dried out.
Animal dung, besides being used as fuel, is occasionally used as a cement to make adobe mud brick huts  or even in throwing sports such as cow pat throwing or camel dung throwing contests.
See also Fewmets for the use of faeces in Venery, or Hunting in the Middle_Ages
See also Kopi Luwak
Kopi Luwak (pronounced ) or Civet coffee is coffee made from coffee berries which have been eaten by and passed through the digestive tract of the Asian Palm Civet (Paradoxurus hermaphroditus).