Human feces also known as a
stool, is the waste product of the human digestive system including bacteria. It varies significantly in appearance, according to the state of the digestive system,
dietIn nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...
and general
healthHealth is the level of functional or metabolic efficiency of a living being. In humans, it is the general condition of a person's mind, body and spirit, usually meaning to be free from illness, injury or pain...
.
Normally stool is semisolid, with a mucus coating. Small pieces of harder, less moist feces can sometimes be seen impacted on the distal (leading) end. This is a normal occurrence when a prior bowel movement is incomplete, and
fecesFeces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
are returned from the
rectumThe rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...
to the
intestineIn human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
, where water is absorbed.
MeconiumMeconium is the earliest stools of an infant. Unlike later feces, meconium is composed of materials ingested during the time the infant spends in the uterus: intestinal epithelial cells, lanugo, mucus, amniotic fluid, bile, and water. Meconium is almost sterile, unlike later feces, is viscous and...
(sometimes erroneously spelled
merconium) is a newborn baby's first feces.
Bristol Stool Chart
The Bristol Stool Chart or Bristol Stool Scale is a medical aid designed to classify the form of human feces into seven categories. Sometimes referred to in the UK as the "Meyers Scale," it was developed by K.W.Heaton at the
University of BristolThe University of Bristol is a public research university located in Bristol, United Kingdom. One of the so-called "red brick" universities, it received its Royal Charter in 1909, although its predecessor institution, University College, Bristol, had been in existence since 1876.The University is...
and was first published in the
Scandinavian Journal of Gastroenterology in 1997. The form of the stool depends on the time it spends in the
colonThe colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
.
The seven types of stool are:
- Separate hard lumps, like nuts (hard to pass)
- Sausage-shaped but lumpy
- Like a sausage but with cracks on the surface
- Like a sausage or snake, smooth and soft
- Soft blobs with clear-cut edges
- Fluffy pieces with ragged edges, a mushy stool
- Watery, no solid pieces. Entirely Liquid
Types 1 and 2 indicate
constipationConstipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...
. Types 3 and 4 are optimal, especially the latter, as these are the easiest to
passDefecation is the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum...
. Types 5–7 are associated with increasing tendency to
diarrheaDiarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
or urgency.
Color variations of feces
Human fecal matter varies significantly in appearance, depending on diet and health. Normally it is semisolid, with a mucus coating. It normally has a brown coloration, which results from a combination of
bileBile or gall is a bitter-tasting, dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the process of digestion of lipids in the small intestine. In many species, bile is stored in the gallbladder and upon eating is discharged into the duodenum...
and
bilirubinBilirubin is the yellow breakdown product of normal heme catabolism. Heme is found in hemoglobin, a principal component of red blood cells. Bilirubin is excreted in bile and urine, and elevated levels may indicate certain diseases...
that is derived from dead
red blood cellsRed blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
.
Yellow
Yellowing of feces can be caused by an infection known as
GiardiasisGiardiasis or beaver fever in humans is a diarrheal infection of the small intestine by a single-celled organism Giardia lamblia. Giardiasis occurs worldwide with a prevalence of 20–30% in developing countries. In the U.S., 20,000 cases are reported to the CDC annually, but the true annual...
, which derives its name from
GiardiaGiardia is a genus of anaerobic flagellated protozoan parasites of the phylum Metamonada in the supergroup "Excavata" that colonise and reproduce in the small intestines of several vertebrates, causing giardiasis, commonly known as Beaver fever...
, an
anaerobicAn anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It could possibly react negatively and may even die if oxygen is present...
flagellated protozoan parasite that can cause severe and communicable yellow
diarrheaDiarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
. Another cause of yellowing is a condition known as
Gilbert's SyndromeGilbert's syndrome , often shortened to GS, also called Gilbert-Meulengracht syndrome, is the most common hereditary cause of increased bilirubin and is found in up to 5% of the population...
. This condition is characterized by
jaundiceJaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...
and hyperbilirubinemia when too much
bilirubinBilirubin is the yellow breakdown product of normal heme catabolism. Heme is found in hemoglobin, a principal component of red blood cells. Bilirubin is excreted in bile and urine, and elevated levels may indicate certain diseases...
is present in the circulating blood.
Black
Feces can be black due to the presence of red blood cells that have been in the intestines long enough to be broken down by digestive enzymes. This is known as
melenaIn medicine, melena or melaena refers to the black, "tarry" feces that are associated with gastrointestinal hemorrhage. The black color is caused by oxidation of the iron in hemoglobin during its passage through the ileum and colon.-Melena vs...
, and is typically due to
bleedingBleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
in the upper digestive tract, such as from a bleeding
peptic ulcerA peptic ulcer, also known as PUD or peptic ulcer disease, is the most common ulcer of an area of the gastrointestinal tract that is usually acidic and thus extremely painful. It is defined as mucosal erosions equal to or greater than 0.5 cm...
. The same color change can be observed after consuming foods that contain a substantial proportion of animal blood, such as Black pudding or Tiết canh. Black feces can also be caused by a number of medications, such as
bismuth subsalicylateBismuth subsalicylate, with a nominal chemical formula of C7H5BiO4, It is a colloidal substance obtained by hydrolysis of bismuth salicylate . The actual structure is unknown and the formulation is only approximate. Recent evidence indicates that it is composed of a bismuth oxide core structure...
(the active ingredient in Pepto-Bismol), and dietary
iron supplementsIron supplements are supplements that can be prescribed by a doctor for a medical reason. Iron can also be a dietary supplement, which can be purchased in supermarkets etc. These two categories should not be confused....
, or foods such as
beetrootThe beetroot, also known as the table beet, garden beet, red beet or informally simply as beet, is one of the many cultivated varieties of beets and arguably the most commonly encountered variety in North America, Central America and Britain.-Consumption:The usually deep-red roots of beetroot are...
, black
liquorice, or blueberries.
HematocheziaHematochezia is the passage of fresh blood per anus, usually in or with stools . Hematochezia is commonly associated with lower gastrointestinal bleeding, but may also occur from a brisk upper GI bleed...
is similarly the passage of feces that are bright red due to the presence of undigested blood, either from lower in the digestive tract, or from a more active source in the upper digestive tract.
AlcoholismAlcoholism is a broad term for problems with alcohol, and is generally used to mean compulsive and uncontrolled consumption of alcoholic beverages, usually to the detriment of the drinker's health, personal relationships, and social standing...
can also provoke abnormalities in the path of blood throughout the body, including the passing of red-black stool.
Blue
Prussian bluePrussian blue is a dark blue pigment with the idealized formula Fe718. Another name for the color Prussian blue is Berlin blue or, in painting, Parisian blue. Turnbull's blue is the same substance but is made from different reagents....
, used in the treatment of
radiationAcute radiation syndrome also known as radiation poisoning, radiation sickness or radiation toxicity, is a constellation of health effects which occur within several months of exposure to high amounts of ionizing radiation...
, cesium, and
thalliumThallium is a chemical element with the symbol Tl and atomic number 81. This soft gray poor metal resembles tin but discolors when exposed to air. The two chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861 by the newly developed method of flame spectroscopy...
poisoning, can turn the feces blue. Substantial consumption of products containing blue food dye, such as blue curaçao or grape soda, can have the same effect.
Silver
A tarnished-silver or aluminum paint-like feces color characteristically results when biliary obstruction of any type (white stool) combines with
gastrointestinal bleedingGastrointestinal bleeding or gastrointestinal hemorrhage describes every form of hemorrhage in the gastrointestinal tract, from the pharynx to the rectum. It has diverse causes, and a medical history, as well as physical examination, generally distinguishes between the main forms...
from any source (
black stoolIn medicine, melena or melaena refers to the black, "tarry" feces that are associated with gastrointestinal hemorrhage. The black color is caused by oxidation of the iron in hemoglobin during its passage through the ileum and colon.-Melena vs...
). It can also suggest a
carcinomaCarcinoma is the medical term for the most common type of cancer occurring in humans. Put simply, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that generally arises from cells originating in the endodermal or ectodermal germ layer during...
of the ampulla of Vater, which will result in gastrointestinal bleeding and biliary obstruction, resulting in silver stool.
Fecal contamination
A quick test for fecal contamination of water sources or soil is a check for the presence of
E. coliEscherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
bacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
performed with the help of
MacConkey agarMacConkey agar is a culture medium designed to grow Gram-negative bacteria and stain them for lactose fermentation.-Contents:It contains bile salts MacConkey agar is a culture medium designed to grow Gram-negative bacteria and stain them for lactose fermentation.-Contents:It contains bile salts...
plates or
Petri dishA Petri dish is a shallow glass or plastic cylindrical lidded dish that biologists use to culture cells or small moss plants. It was named after German bacteriologist Julius Richard Petri, who invented it when working as an assistant to Robert Koch...
es.
E. coli bacteria uniquely develop red colonies at temperature of approximately 43 °C (109.4 °F) overnight. Although most strains of
E. coli are harmless, their presence is indicative of fecal contamination, and hence an increased possibility of the presence of more dangerous organisms.
Fecal contamination of water sources is highly prevalent worldwide, accounting for the majority of unsafe
drinking waterDrinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually...
. In developing countries most sewage is discharged without treatment. Even in developed countries events of
sanitary sewer overflowSanitary sewer overflow is a condition whereby untreated sewage is discharged into the environment prior to reaching treatment facilities thereby escaping wastewater treatment. When caused by rainfall it is also known as wet weather overflow. It is primarily meaningful in developed countries,...
are not uncommon and regularly pollute the Seine River (
FranceThe French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
) and the
River ThamesThe River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...
(
EnglandEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
), for example.
The main pathogens that are commonly looked for in feces include:
- Bacteroides
Bacteroides is a genus of Gram-negative, bacillus bacteria. Bacteroides species are non-endospore-forming, anaerobes, and may be either motile or non-motile, depending on the species. The DNA base composition is 40-48% GC. Unusual in bacterial organisms, Bacteroides membranes contain sphingolipids...
species
- Salmonella
Salmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
and ShigellaShigella is a genus of Gram-negative, nonspore forming, non-motile, rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella causes disease in primates, but not in other mammals. It is only naturally found in humans and apes. During...
- Yersinia
Yersinia is a genus of bacteria in the family Enterobacteriaceae. Yersinia are Gram-negative rod shaped bacteria, a few micrometers long and fractions of a micrometer in diameter, and are facultative anaerobes. Some members of Yersinia are pathogenic in humans; in particular, Y. pestis is the...
tends to be incubated at 30 °C (86 °F), which is cooler than usual
- Campylobacter
Campylobacter is a genus of bacteria that are Gram-negative, spiral, and microaerophilic. Motile, with either unipolar or bipolar flagella, the organisms have a characteristic spiral/corkscrew appearance and are oxidase-positive. Campylobacter jejuni is now recognized as one of the main causes...
incubated at 42 °C (107.6 °F), in a special environment
- Aeromonas
Aeromonas is a gram-negative, facultative anaerobic rod that morphologically resembles members of the family Enterobacteriaceae. Fourteen species of Aeromonas have been described, most of which have been associated with human diseases. The most important pathogens are A. hydrophila, A. caviae, and...
- Candida
Candida is a genus of yeasts. Many species are harmless commensals or endosymbionts of animal hosts including humans, but other species, or harmless species in the wrong location, can cause disease. Candida albicans can cause infections in humans and other animals, especially in immunocompromised...
if the person is immunosuppressed (e.g., undergoing cancer treatment)
- E. coli O157
Escherichia coli O157:H7 is an enterohemorrhagic strain of the bacterium Escherichia coli and a cause of foodborne illness. Infection often leads to hemorrhagic diarrhea, and occasionally to kidney failure, especially in young children and elderly persons...
if blood is visible in the stool sample
- Cryptosporidium
Cryptosporidium is a protozoan that can cause gastro-intestinal illness with diarrhea in humans.Cryptosporidium is the organism most commonly isolated in HIV positive patients presenting with diarrhea...
- Entamoeba histolytica
Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 50 million people worldwide...
Diarrhea
Many viruses, parasites and bacteria cause
diarrheaDiarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
. Diarrhea occurs when the
large intestineThe large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...
fails to reabsorb water to the normal extent. This results in a very liquid stool, increasing the rate of expulsion of the intestinal
pathogensA pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
.
Fecal markers
The feces can be analyzed for various markers that are indicative of various diseases and conditions. For example,
fecal calprotectinMeasurement of faecal calprotectin is a biochemical test for inflammatory bowel disease. It replaces the need for invasive colonoscopy or radio-labelled white cell scanning in many clinical scenarios.-Structure and function:...
levels indicate an inflammatory process such as
Crohn's diseaseCrohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
,
ulcerative colitisUlcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...
and neoplasms (
cancerCancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
).
| Reference ranges for fecal markers |
| Marker |
Patient type |
Upper limit |
Unit |
| Calprotectin Measurement of faecal calprotectin is a biochemical test for inflammatory bowel disease. It replaces the need for invasive colonoscopy or radio-labelled white cell scanning in many clinical scenarios.-Structure and function:...
|
2–9 years |
166 |
µg In the metric system, a microgram is a unit of mass equal to one millionth of a gram , or 1/1000 of a milligram. It is one of the smallest units of mass commonly used...
/g of feces |
| 10–59 years |
51 |
| ≥ 60 years |
112 |
| Lactoferrin Lactoferrin , also known as lactotransferrin , is a multifunctional protein of the transferrin family. Lactoferrin is a globular glycoprotein with a molecular mass of about 80 kDa that is widely represented in various secretory fluids, such as milk, saliva, tears, and nasal secretions...
|
2–9 years |
29 |
| ≥ 10 years |
4.6 |
Also, feces may be analyzed for any
fecal occult bloodFecal occult blood refers to blood in the feces that is not visibly apparent. A fecal occult blood test checks for hidden blood in the stool...
, which is indicative of a
gastrointestinal bleedingGastrointestinal bleeding or gastrointestinal hemorrhage describes every form of hemorrhage in the gastrointestinal tract, from the pharynx to the rectum. It has diverse causes, and a medical history, as well as physical examination, generally distinguishes between the main forms...
.
See also
- Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
- Composting toilet
A composting toilet is a dry toilet that using a predominantly aerobic processing system that treats excreta, typically with no water or small volumes of flush water, via composting or managed aerobic decomposition...
- Coprophilia
Coprophilia , also called scatophilia or scat, is the paraphilia involving sexual pleasure from feces...
- Constipation
Constipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...
- Defecation
Defecation is the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum...
- Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
- Ecological sanitation
Ecological sanitation, also known as ecosan or eco-san, are terms coined to describe a form of sanitation that usually involves urine diversion and the recycling of water and nutrients contained within human wastes back into the local environment....
- Humanure
- Meconium
Meconium is the earliest stools of an infant. Unlike later feces, meconium is composed of materials ingested during the time the infant spends in the uterus: intestinal epithelial cells, lanugo, mucus, amniotic fluid, bile, and water. Meconium is almost sterile, unlike later feces, is viscous and...
- Night soil
Night soil is a euphemism for human excrement collected at night from cesspools, privies, etc. and sometimes used as a fertilizer. Night soil is produced as a result of a waste management system in areas without community infrastructure such as a sewage treatment facility, or individual septic...
- Outhouse
An outhouse is a small structure separate from a main building which often contained a simple toilet and may possibly also be used for housing animals and storage.- Terminology :...
- Scatology
In medicine and biology, scatology or coprology is the study of feces.Scatological studies allow one to determine a wide range of biological information about a creature, including its diet , healthiness, and diseases such as tapeworms. The word derives from the Greek σκώρ In medicine and biology,...
- Shit
Shit is usually considered vulgar and profane in Modern English. As a noun it refers to fecal matter and as a verb it means to defecate or defecate in; in the plural it means diarrhea...