About 70-80% of an "average" human poop consists of water. Water is absorbed out of fecal material as it passes through the intestine, so
the longer a poop resides inside before emerging, the drier it will be.
Much of the remaining portion of the poop, about 1/3 is composed of dead bacteria.
These microcorpses come from the intestinal garden of microorganisms that assist us in the digestion of our food.
Another 1/3 of the poop mass is made of stuff that we find indigestible, like cellulose, for instance.
This indigestible material is called "fiber," and is useful in getting the poop to move along through the intestine, perhaps because it provides traction.
The remaining portion of poop is a mixture of fats such as cholesterol, inorganic salts like phosphates, live bacteria, dead cells and mucus from the lining of the intestine, and protein.
Poop has an odor ("stinks") as a result of the products of bacterial action. Bacteria produce smelly,
organic compounds such as indole, skatole, and mercaptans, and the inorganic gas hydrogen sulfide. These are the same compounds that give farts their odor.
The color comes mainly from bilirubin, a pigment that arises from the breakdown of red blood cells in the liver and bone marrow. The actual metabolic pathway
of bilirubin and its byproducts in the body is very complicated, so we will simply say that a lot of it ends up in the intestine, where it is
further modified by bacterial action. But the color itself comes from iron. Iron in hemoglobin in red blood cells gives blood its red color, and iron
in the waste product bilirubin gives rise to its brown color.
Poop is mostly shades of brown or yellow, but other colors can arise under certain circumstances. For example, someone with a bleeding ulcer might have tarry black poop
from the presence of partially digested blood. Bleeding in the intestine, from an anal fissure or split, for example, can stain the poop red. Some
illnesses in babies gives them green or even blue-green poop. But another source of blue poop in children is more innocent: it can come from eating
a concentrated source of blue food coloring such as ice cream. Intense red food coloring can produce bright red poop. Sometimes brightly colored
foods pass through the gut almost unchanged, and the poop may be speckled with bright red fragments such as pimentos, or bright yellow kernels of corn.
Many animals eat poop on a regular basis. These include rabbits, rodents, gorillas, many insects such as dung beetles and flies, and yes, dogs. (Keep that in mind
the next time a dog wants to lick you!) Herbivores such as rabbits and rodents eat their own poop because their diet of plants is hard to digest
efficiently, and they have to make two passes at it to get everything out of the meal. This is equivalent to a cow chewing its cud, only cows are
able to re-eat their food without having to poop it out first. Another reason why animals eat poop is that poop contains vitamins produced by
their intestinal bacteria. The animal is unable to absorb the vitamins through the intestinal wall, but can get at them by eating the poop. Another
reason that animals such as dogs and flies eat poop is that poop contains a certain amount of protein. Dogs are particularly fond of cat poop because cat poop is high in protein.
People all have eaten poop at one point or another. One of the main ways that diseases and parasites spread is through the consumption of food and water contaminated with feces.
This happens because people don't wash their hands carefully after pooping or changing a diaper or scratching their butt. It can also happen through careless disposal of diapers.
You can definitely get sick from eating poop, even in minute quantities! Although urine emerges sterile from the body (unless the person has an infection),
poop emerges loaded with bacteria and sometimes other life forms. Many diseases, including food poisoning, cholera and typhus, are spread by fecal
contamination. Many parasites, such as the notorious tapeworm, can be spread through deliberate or accidental ingestion of poop.
There are some parasites, such as pinworms, who depend on people eating their own poop to keep the population up. Pinworms are small nematodes that live in the
colon. The females emerge from the anus at night to lay their eggs. Their activity makes the anal area itch. The person scratches the itch (often
doing so in his sleep), procuring a small amount of fecal matter and eggs under his fingernails, and then puts his fingers in his mouth. Once the
eggs are consumed, the person is infected with a new generation of pinworms.
Many people have pinworms. Luckily, pinworms don't do much harm. You only notice them if you have a lot of pinworms! If you want to find out if you do indeed
have them, get someone to gently touch around your anal area with Scotch tape while you are sleeping. The worms will stick to the tape and you'll be able to see them.
Diarrhea is genrally caused by irritation in the intestines, resulting in the bowel passing its contents too fast for the water to be absorbed.
There can be several causes, including infection by bacteria or viruses, irritation caused by unfamiliar foods,
food allergies, chronic illnesses such as inflammatory bowel disease, lactose intolerance, medications, and nervousness.
Corn poop is one of the mysteries in life. When we chew corn, the outer coating slips off the inner kernal. This outer yellow coating
is almost entirely cellulose, and is indigestible. It passes through the gut untouched, and emerges looking like a whole kernel, although it is
mostly just the outer skin. The inside of the kernel is starchy and digestible, and that is the part that we succeed in chewing up.
In humans, soft poop is really one long, mostly continuous sausage before it comes out.
It gets its "link" look because we tend to pinch off lengths of it with the anal sphincter as the poop emerges.
If a person pinches hard enough, the poop separates into several poop units. If the person doesn't pinch that hard, the turds may stay connected.
"Floaters" are turds that have an unusually high gas content. Sometimes the gases produced by bacteria in our gut don't have a chance to collect into a large fart
bubble, but remain dispersed in the feces. The poop then comes out foamy, and has a lower density than water.
Turds can get very large and dry if a person is constipated, causing painful stretching of the anal opening. Pooping can also hurt if the person has hemorrhoids.
Hemorrhoids are engorged veins in the anal area. A doctor once described them to me as "varicose veins of the anus," which suggests that the valves
in the veins that are supposed to keep the blood flowing in the right direction have gotten messed up. Pooping can also be painful if the person suffers
from an anal fissure, a tear in the tissue of the rectum.
Meat protein is rich in sulfides, resulting in smellier farts and poop. This is the reason that the poop of carnivores such as dogs, cats and snakes smells worse than the poop of herbivores such as cows and horses.
There are many thoughts on the matter of where the word "poop" came from. According to
Eric Partridge in his excellent book of word origins (Origins: A Short Etymological Dictionary of Modern English), "poop" comes from the Middle
English word poupen or popen, and it originally meant "fart." According to Robert Chapman, author of American Slang, "poop" came into use with its current meaning around 1900.