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Why Is My Poop Black? How Poop Color Can Be Informative

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Why Is My Poop Black? How Poop Color Can Be Informative

Jan 23, 2020

The human body is a complicated and sometimes bizarre specimen. With trillions of cells and dozens of interconnected organs and systems, our bodies are a marvel of natural complexity and a testament to the wonders of evolution. Yet as sophisticated and resilient as the human body is, we can’t escape its less pleasant aspects. The truth is, the human body is finicky and requires a lot of maintenance — trimming, clipping, cleaning, etc. — and it can also be pretty gross. 

Arguably the grossest and most taboo aspect of our bodies is the fact that we poop. Indeed, many people are even uncomfortable talking about it; or they need to cover their discomfort by making jokes (comedians have been doing it for years). That taboo isn’t very useful when it comes to being open about our health issues, however, especially given the fact that the state of our poop (referred to as stool in medical contexts) can speak volumes about the state of our health.

So what does it say about your health when you look down in the toilet and see stool that is black? Is it healthy? Having stool that is black and tarries with consistency can be pretty alarming. In truth, almost any color that deviates from the normal brown can be cause for concern. Before understanding what black stool color (or any color) can tell us, it’s important to understand how stool is even formed in the first place. 

What happens during digestion?

The digestive process begins, of course, with the consumption of food. As food is chewed, the combination of teeth and saliva mash it into an easily-swallowable pulp that is then pushed into the esophagus by the tongue. After the masticated food moves down your esophagus and into the stomach, powerful stomach muscles work with digestive juices to break down the food into a semi-fluid substance called chyme. 

This chyme enters then enters the small intestine, where it mixes with additional digestive juices from the liver, pancreas, and intestines; these juices contain enzymes that aid in digestion and the absorption of nutrients. As the chyme is pushed along the small intestine (a distance of 20 feet!), water is absorbed and starches, proteins, and carbohydrates are further broken down into components that can be taken into the bloodstream. 

The final stage of digestion happens when the resulting semi-fluid waste materials from the small intestine enter the large intestine (otherwise known as the colon). This waste material includes fluid, undigested food, and discarded cells that are either damaged or degraded. In the colon, most of the water is absorbed as solid stool is formed. The stool makes its way through the colon through a series of autonomic muscle contractions called peristalsis and then out through the rectum and anus. 

What does my poop color tell me about my health? 

It is because of the complexity involved in all the digestive steps described above that many different factors come into play when stool is formed. Those factors all contribute to the overall health of the digestive system and the resulting stools. Color, along with texture, size, shape, and solidness, is one way of determining digestive health. 

But how does the color of stool actually indicate something specific about what’s happening in one’s body? Much of the time, the color comes from dietary content; what and how much you eat, what you drink, etc. Yet different stool colors can also come about because of disease or as a side effect of some underlying condition. 

While there are no hard and fast rules about stool color and the precise cause, there are some common connections that doctors have identified. Here are some of the possible stool colors that people can experience and their possible related causes:

  • Brown: All shades of brown are generally considered normal and healthy. 
  • Green: Green stool can be just as healthy as brown, particularly if it is due to an abundance of leafy green vegetables (or green food coloring); it can also result from taking iron supplements. When paired with very loose stools (such as in diarrhea), it can indicate that food is moving through the colon too quickly and therefore the bile introduced in the small intestine doesn’t have a chance to break down completely. 
  • Pale: Very light or clay-colored stool might point to a lack of bile that in turn could indicate a blocked bile duct. There are also some over-the-counter medications that use bismuth subsalicylate; these medications used to treat diarrhea may, in large doses, cause stool to be pale. 
  • Yellow: Usually also greasy and with an especially foul odor, yellow stool could indicate a malabsorption disorder like celiac disease; the yellow color comes from excessive fat in the stool that wasn’t able to be absorbed during digestion. In relatively rare cases, the gluten in bread and cereals may also cause a yellowish color.
  • Red: When stool is bright red, it is usually a sign of bleeding in the lower gastrointestinal tract; hemorrhoids is a common culprit. It is also possible after having eaten red foods like beets or tomato juice or foods with red food coloring. 

What does black poop mean?

But what about black stool? While it isn’t necessarily any worse than other color possibilities, it has its own unique properties. One of the most concerning reasons why stool might be black is bleeding in the upper gastrointestinal tract. The stool that results from this kind of bleeding is called melena, and it refers both to the black color and the tarry consistency. The hemoglobin in the blood that makes its way through the gastrointestinal tract is reacted upon by various digestive enzymes and intestinal bacteria; the net effect of this process is black and tarry stool.

There are numerous potential causes of this kind of bleeding, but one of the most common causes is having peptic ulcers, which are painful sores that can develop on the inner lining of your stomach or other parts of your digestive tract. When sufficiently irritated, these sores can bleed, and the blood will make its way through the rest of the digestive tract and become incorporated into the stool. One much more rare possibility related to bleeding is esophageal or gastric cancer.

Apart from bleeding, there are a number of other diet-related causes that can also be at play. One possibility is dark-colored foods like black licorice or beets. Black stool can also be a side effect of taking iron supplements, a key part of treating anemia; the extra iron not absorbed by the bloodstream can travel through the digestive tract and be passed out in the stool. Similarly, over-the-counter medications for an upset stomach like Pepto-Bismol (bismuth subsalicylate) can also cause black, tarry stool. 

Treatment Options for Black Stools

The treatment for black stool is totally dependent on the source of the color. That is why the first question to ask when you see black stool is: what did I eat recently? Some simple dietary changes can resolve the problem overnight. If the stool is melena, the dark and tarry result of gastrointestinal bleeding, then the treatment will vary depending on the underlying cause. 

Gastroenterologist Appointment 

If you have been having black stools and you can’t rule out dietary supplements or dark-colored foods in your diet, it might be time to consult a gastroenterologist. You’ll want to be checked out so that you can be sure there isn’t a more concerning problem in your digestive system. To make an appointment with a highly skilled gastroenterologist, contact Carolina Digestive today. They are dedicated to providing the highest quality care for any and all gastrointestinal concerns.