I took my 2 year old daughter for a walk through the now-devoid-of-cattle pasture the other day. She has just entered the ”why?” phase, so she is full of questions. While we walked, I had to help her avoid the poop bombs left behind by the previous owner’s cattle.

”Don’t step in the cow poop.”

”Why?”

”Because I don’t want you to get it on your shoes.”

”Why?”

”Because I don’t want you to track it into the house.”

”Why?”

”Because poop stinks.”

”Is that poop brown?”

”Yes, that is brown.”

”Is my poop brown?”

”Yep, your poop is brown, too.”

”Why is my poop brown?”

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Why Is My Poop Brown?

That’s a pretty good question from a 2 year old. It got me wondering. I mean, I kind of knew, but I figured that the answer had to be more complex and detailed. I thought I’d just do a little bit of digging to find out more, but I soon found myself flushed away; floating in a sea of knowledge… about poo.

Mind if I smear a little bit of it on you?

Everybody Poops

For some, it’s a daily routine. For others, it may only happen every day or two. Experts claim that either way can be normal depending on your diet and body chemistry. But, you gotta do it! Not only is pooping the way that the body gets rid of the parts of food that it can’t use/process, but it is also very important in ridding the body of other metabolic wastes that would otherwise build up to toxic levels.

According to one study, the average healthy human poops about 1.2 times every 24 hours, relieving themselves of about 106.67 g of waste with each sitting. That comes out to about 128 grams of poo every day.

What Is In My Poo?

Apparently, most (74.6%) of the mass of your poo comes from water. Of course, this is just an average. If you are dehydrated, or if you just have a naturally slower digestive tract, your poop may be drier than average. On the other hand, if your waste has made a quick exit for whatever reason (stress, virus, allergic reaction to food, etc.), your stool may have more water in it. This is because the large intestine is where most of the water from your food/drink is absorbed. The more time it spends in the large intestine, the drier it will be. Alternatively, the faster it passes through, the wetter it will be. Of the remaining ~25% of the mass, anywhere from 25%-54% is made up of bacteria, viruses, and archaea - both living and dead. There is also some fiber, little pieces of undigested food, excess vitamins and minerals that your body couldn’t use, and metabolic wastes in there. But, which of these things gives poop its brown color?

Why Is Poop Brown?

Going into this article, my answer to this question would have had something to do with dead red blood cells and bilirubin; and, while those two components do have something to do with it, I had no idea about the mechanism by which it occurs.

The average red blood cell has a lifespan of 120 days. So, what happens to all of those dead blood cells? They have to be eliminated from the body; otherwise, the iron contained within them can build up in the bloodstream and damage the kidneys. This happens in the liver where the heme - the molecule that contains the iron - is converted to a chemical called bilirubin. This is a two-step process. First, an enzyme called heme oxygenase frees the iron from the heme yielding a molecule called biliverdin. Then, another enzyme called biliverdin reductase turns it into bilirubin.

Bilirubin is a yellow colored chemical that may act as an antioxidant in the body. It is insoluble and actually quite toxic if it builds up in the body. In fact, it is the chemical responsible for the yellowish appearance of the skin in people suffering from jaundice, and it gives bruises the yellowish color that you see when it is healing. Bilirubin is also a component that makes up bile. Bile is a green colored substance produced by the liver and stored in the gallbladder. During digestion, bile is squirted into the small intestine where it helps to break down fats and oils. Some of the bile that goes unused is broken down by bacteria in the gut, and during that process, the bilirubin is converted to a chemical called sterobilin. That is the stuff that makes your poop brown!

Phew! That was complicated. But, at least now you know why your poop is the color that it is!

Wait.

What?

Your poop isn’t brown, you say?

Well, what color is it?

In my research, I learned that your poop can be a whole rainbow of different colors (not at the same time, of course. That would be…AWESOME!). Sometimes these different colors can be caused by completely innocuous reasons; however, they may also be a sign of really bad problems going on internally.

My Poop Is Gray or White

Gray, white, or even clay colored stool is a sign that there isn’t enough bile getting into your digestive tract. This is the natural color of the stuff that your body has broken down minus the sterobilin produced from the bilirubin in your bile. If you notice that your poop is this color, you should go to the doctor, as it could be caused by a range of things from gallstones blocking the bile ducts to cirrhosis, or even cancer.

My Poop Is Green

Having green poop can be caused by several factors. Crap, some people just normally poop green hues. It can also be caused by eating lots of leafy green vegetables or even blueberries. However, sometimes green poo can be caused by excess bile in the gut due to any number of things. If your stool remains green for several days or if it is accompanied by any sort of GI distress (diarrhea, vomiting, upset stomach, etc.), then you should definitely get it checked out.

My Poop Is Red

Red poop can also be caused by something you ate. One time, our baby had red poop. I was kind of freaking out until I found out that she had eaten a whole bunch of birthday cake with red icing. However, red in your poo can also be a sign of blood in your stool. If so, it may indicate an intestinal tract infection, stomach ulcer, or even more serious conditions such as cancer. This is definitely something that you want to get checked out.

My Poop Is Kind Of Purple

If you love beets, then this may be a common experience for you. However, if beets aren’t in your diet, and you find yourself pooping purple, go to the emergency room. Purple poop could indicate internal bleeding due to any number of things.

My Poop Is Black

This is another possible indicator of major problems, as it could also be caused by internal bleeding. It may also be caused by the bismuth in medications like Pepto Bismol. If this is the case, then it’s no big deal. However, the alternatives are bad enough that you shouldn’t take the chance. If your stool is black, go to the doctor.

My Poop Is Yellow

Of course, yellow poop can be caused by something that you ate. Alternately, it could indicate an intestinal infection like giardia. It may also be a symptom of celiac disease or cystic fibrosis, and it may even be caused by pancreatic disease. If you have persistent yellow poop, get it checked out.

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Sources

Numbertwoguide.com - What Is Poop?

The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology. Rose C, Parker A, Jefferson B, Cartmell E.

Scientific American - What’s In Your Poo?

EliteDaily.com - *This Is Exactly What Your Poop Is Made Of

Every Day Health - The Many Shades Of Poop and What They Mean

MedicineNet.com - *Stool Color, Changes in Color, Texture, and Form
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Bilirubin and glutathione have complementary antioxidant and cytoprotective roles - Thomas W. Sedlak, Masoumeh Saleh, Daniel S. Higginson, Bindu D. Paul, Krishna R. Juluri, and Solomon H. Snyder

Gastrointestinal Physiology - Mcgraw Hill

Healthline - What Causes Pale Stools