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Stool Abnormalities: Mucus, Blood, and Color (With Pictures)

Updated on May 8, 2017
mistyhorizon2003 profile image

The author formerly worked at a veterinary practice in the Channel Islands. Her interests include fishing, gardening, and singing.

How to Analyze Poop

I wanted to pick a topic that was completely different from the normal stuff. What could be better than giving you the information you need to know in order to examine your stools to determine if you are living a healthy lifestyle?

In this article, I go in-depth on various poo colors and textures and what they might mean for you. But first, let's look at a quick chart about two commonly asked questions: what do mucus and blood in the stool look like?

What Do Mucus and Blood in the Stool Look Like?

Mucus is a white or yellow jelly-like, squishy substance that can look like streaks or blobs.
A small amount of mucus in your stool is nothing to be concerned about; large amounts of mucus or mucus accompanied with blood or pus can be the result of a number of infections or conditions (see below) and should be investigated by a doctor.
Blood in your stool can vary in appearance. It can be bright red and be streaked or spotted. Your poo may also be tarry and dark (called melena), which is an indication of bleeding in a higher area of the GI tract.
Bright red blood can be caused by a number of conditions including anal fissures and hemorrhoids, while dark tarry stools can be caused by a variety of other conditions. See below for more information.

Picture of Mucus in Stool

Did You Know?

•It's normal to poop anywhere from three times a day to once every three days.

•If your stool smells really foul, you may be ingesting too many animal proteins.

•Excess mucus could be a sign you're eating foods you're allergic to.

Abnormal Stools

An abnormal stool can vary from person to person since regular stools also vary from person to person. Many changes in stools can be accounted for by dietary changes.

Blood, tons of mucus, or bloody mucus in your stool is always a cause for concern, especially if it's accompanied by abdominal pain or other symptoms.

Chronic constipation and diarrhea are also things you should bring up with your doctor.

Some changes in your stool can be caused by eating different kinds of food, food that has gone bad, or food with artificial dyes or colorings.

Keeping track of your stools, taking pictures, and keeping a stool diary will also help you recognize patterns that you can bring to the attention of your healthcare provider.

According to HealthLine, you should seek immediate medical attention if you have any of the following changes in bowel habits:1

  • blood in your stool
  • increased mucus in your stool
  • watery, diarrhea-like stools for over 24 hours
  • pus in your stool
  • severe abdominal pain

And you should make plans to see the doctor if:

  • You haven't pooped in three days
  • You can't pass gas
  • You have mild, persistent abdominal pain
  • You have lost the ability to control your bowels and have sudden urges to have a bowel movement
  • You're losing weight for no apparent reason
  • You have thin, ribbon-like stools

Mucus in Stool

Mucus is in your bowels to protect the lining of the intestines and help things pass more easily.2 A little mucus is normal, but whenever your poop has an excessive amount of mucus in it (a clear, white, or yellow substance with the consistency of jelly which is produced by the mucus membrane of the large intestine), you should get it checked out. This is especially true if it's accompanied by bleeding or a change in bowel habits.3

A significant, prolonged increase in the amount of mucus in the stool is a potential sign of potential disorders such as Crohn’s disease, cystic fibrosis, irritable bowel syndrome, or a malabsorption issue such as celiac disease or lactose intolerance.2 You should let your doctor know about the presence of increased mucus, pus, or blood in your stool.

A Visual Explanation of Mucus in Stool

Blood in the Stool

According to UptoDate,4 seeing blood on the outside of your stool, on toilet paper after wiping, or in the toilet is fairly common and most of the times, it is not the result of a dangerous medical issue. This kind of rectal bleeding (which appears as bright red blood) is most commonly caused by hemorrhoids and anal fissures.

However, there are some other, more serious, causes of rectal bleeding such as colon cancer, colon polyps, and diverticulosis. It is impossible to distinguish one from the other without a medical exam. So if you've been experiencing rectal bleeding for a significant period of time, you should see a healthcare professional.

Bleeding from higher up in the GI tract, such as in the stomach, can cause black, tarry stools. If you're passing blood that is dark red or in clots, it would also indicate bleeding that is higher up than hemorrhoids or anal fissures might cause — these are definitely reasons to see your physician.

Floating Stools

It's not always a bad sign, but floating stools might be an indication of lactose intolerance, gluten sensitivity, bad digestion, or air inside your intestines. This is sometimes an indication that you've been eating something you couldn't digest properly, like desserts, excess dairy, or fatty things like fries.

Malabsorption—when you can't absorb all the fat and other nutrients from the food you're ingesting—can cause your poop to float.5 With a stool diary, you can keep track of what you're eating and how it affects your stools. If you have floating stools for a prolonged period of time (over two weeks), this may be something you want to bring up with your doctor, especially if it's accompanied with other symptoms like abdominal pain.

Ribbon-Like Stools

Skinny, stringy poop may be caused by a condition that triggers inflammation in the colon, like Crohn's disease or ulcerative colitis. It could also be caused by something simple, like constipation due to a lack of fiber in the diet.6

In ulcerative colitis, each time that your intestines heal after being ulcerated, the scar tissue that forms is not as flexible as the tissue that was there before the ulcer. This means that the intestine can't stretch as much as normal so the stool will become smaller.

Whenever you notice sudden drastic changes in your poop, it's something you should mention to your doctor.

Foul-Smelling Stools

Poop isn't supposed to smell good, but when it starts to smell like rotten eggs, take note. Changes in diet are the most common culprit for changes in stool odor, but if this continues for a few days and comes with lots of cramping and diarrhea, then you should let your doctor know.7

Sometimes you may get foul-smelling poop from eating something that didn't sit well with you, but if it's accompanied by changes in the color of the stool, pain, fever or chills, or weight loss, it could also mean something serious, so pay attention.

Foul-smelling stool can also be caused by malabsorption issues, such as lactose intolerance, celiac disease, food allergies, or inflammatory bowel disease, so if this is a persistent issue, you should take steps to find the underlying cause.7

Why Does My Poop Smell So Bad?

What to Do
Changes in diet
The most common reason for odor; something you ate or a natural bacteria in your colon are the culprit
Avoid those foods
Infection or disease is preventing your body from absorbing nutrients
Check for dairy or carbohydrate intolerance or other food allergies, celiac's disease, or inflammatory bowel disease
Bad food
You may have eaten something that was infected with virus or bacteria and wasn't cooked properly
It shouldn't persist after the food has been digested
Medications and vitamins
Antibiotics, medicines, and excess multivitamins can mess with your system
If you have overdosed on your medicine or on vitamins A, D, E, or K, you should tell your doctor
Other conditions
There are many other possible medical explanations
Consult with your doctor

Why Is My Poop Green?

Sometimes this is nothing to worry about. When digested matter goes through the intestines too quickly, it has no time to turn brown, so it comes out green.

Stool Colors and What They Mean

Of course, people do experience other problems with their stools, such as changes of color. How would you feel if you went to the toilet and your poo came out green, black, or red? What does it mean if it floats (or sinks)? Why does it have white stringy stuff running throughout it?

I hope here to explain many of the concerns you all have so that you can sleep at night and not worry why your latest bowel movement was so odd.

Light, Whitish, or Pale

This can be an indication of a lack of bile. Perhaps a bile duct is obstructed, or maybe you've taken too much bismuth subsalicylate (Kaopectate, aka Pepto-Bismol) or some other anti-diarrheal medication? If this persists, this is something you should bring up with your doctor.8


If your poop is yellow, it may be a sign that you haven't properly digested the fat or protein gluten in your diet. Perhaps you have a malabsorption disorder (like celiac disease) or maybe you've just been eating too many fatty foods. Tell your doctor.8


Certain foods (like beets and other things with artificial red coloring) can make your poop look alarmingly bloody, but there is no cause for concern. Real blood, however, can be a sign of a problem. The medical term for the passage of bloody poop is "hematochezia." The brighter the blood is, the lower it may be coming from in the gastrointestinal tract (colon), rather than the higher gastrointestinal tract (esophagus, stomach, small intestine). A physician should always investigate blood in the stool to rule out potentially serious conditions.8


If you have the occasional green poop, don't panic! Most likely it is normal, and there is a perfectly reasonable explanation. Think about the foods you ate or any vitamins or supplements you took, even if they're not green.

There can be many reasons: The first and most obvious is eating green foods. Green, leafy vegetables contain chlorophyll, which could be coloring the stool green. Foods with dark purple coloring, like Kool-Aid, popsicles, and gelatin (Jell-O), can also result in rainbow-colored poop. Iron supplements or foods that are rich in iron can also give it a green tinge.

Poop can also appear green for other reasons, and not just from what you've been eating. We think of a healthy stool as being brown, but the bile secreted in the first part of the small intestine is actually green. As food is digested and passed through the large intestine, it turns into a darker brown color. If it is still green by the time it is excreted, it may have gone through the large intestine too fast to be changed in color. This is often called "rapid transit" or "decreased colonic transit time," and green diarrhea can result.8

In breast-fed infants, green poop is normal, especially right after delivery. In older children, the reason could be food-related as described above, or from eating or sucking on colored non-food items such as crayons.


Black, tarry stools with a foul odor can be the result of eating certain foods, taking iron supplements, or possibly from internal bleeding. If the black color is from blood, it is known as "melena." The dark color indicates that the blood has been in the body for some time and comes from higher up in the gastrointestinal tract.8

Note: A black stool caused by food, supplements, medication, or minerals is known as "false melena." Iron supplements, taken alone or as part of a multivitamin for iron-deficient anemia, may cause poop to be black or greenish in color. Foods that are dark blue or black may also cause blackness. Substances that can cause false melena are:

  • Black licorice
  • Blueberries
  • Iron supplements
  • Lead
  • Bismuth (Pepto-Bismol)

A physician should be consulted immediately if the black color can not be attributed to a benign cause such as an iron supplement or food.

Melena Symptoms and Diagnosis

The black color alone is not enough to determine that blood is being passed in the stool. Therefore, a doctor will need to confirm. This can be done in the office through a rectal exam, or you may be sent home with a kit to collect a small sample that can be sent to a lab for evaluation.

The blood could be the result of several different conditions including a bleeding ulcer, gastritis, esophageal varices, or a tear in the esophagus from violent vomiting (aka a Mallory-Weiss tear). The tarry appearance is from the blood having contact with the body’s digestive juices.

After melena is diagnosed, a physician may order other diagnostic tests to determine the cause and exact location of the bleeding. This could include x-rays, blood tests, colonoscopy, gastroscopy, stool culture, and barium studies.9

Different Kinds of Stool

Below are eight different types of poo you might see in your toilet, based on the Bristol Stool Chart (more information below).

  • Stools at the lower numbers on the scale are hard to pass and often require a lot of straining. If you are constipated, you will be passing type 1 or 2 stools when you pass them at all.
  • Those suffering from diarrhea will pass type 6, 7, or 8 on a frequent basis. Those at the loose or liquid end of the spectrum may seem to pass through your digestive system too easily, causing an urgency to defecate as well as potential “accidents.”
  • Types 3 and 4 are ideal since they are easy to pass without being too watery.

Modified Bristol Stool Chart: Type 8 Is an Addition
Modified Bristol Stool Chart: Type 8 Is an Addition

Bristol Stool Chart Explanation

This chart was developed by a team of gastroenterologists at the University of Bristol. It is now a widely recognized general measurement used in the healthcare profession to evaluate the consistency or form of stools. This scale is a medical tool designed to classify one’s bowel movements into seven distinct categories.10

There is a direct correlation between the shape of the stool and the amount of time it has spent in the colon. Therefore, the Bristol scale can be used to measure the consistency or form of a patient’s stools and present your healthcare provider with information for detecting patterns or changes in bowel habits. However, it’s important to remember that this scale is intended to provide a general, not exact, measurement of fecal form and consistency.

The Bristol Stool Scale classifies feces into seven types, based on their appearance as seen in the toilet water. They are distinguished as follows:

  • Type 1: Feces come out in separate, hard lumps, similar to nuts. Type 1 has spent the longest amount of time in the colon and is generally difficult to pass. When feces sit in the colon for too long, it can cause constipation. This condition is usually caused by a lack of fluids, lack of friendly bacteria, stress, excess mucus, and not enough good fiber, though it can also be a sign of other conditions.
  • Type 2: Lumpy and sausage-like in appearance.
  • Type 3: Comes out looking similar to a sausage but with cracks in the surface.
  • Type 4: Feces are smooth and soft in the form of a sausage or snake.
  • Type 5: Feces form soft blobs with clear-cut edges that are easily passed through the system.
  • Type 6: Fluffy pieces with ragged edges. These are considered mushy stools.
  • Type 7: Entirely liquid and watery with no solid pieces. This type of stool has spent the least time in the colon. Diarrhea is usually caused by a bacterial or virus infection from food or water. It can also be caused by anxiety, food allergy, drugs, or other problems in the colon. This type is a sign that something is wrong, and the body is trying to cleanse itself.
  • Type 8: This type was not included in the original Bristol Stool Scale, but was added later by Dr. Group. It is foul-smelling and mucus-like with bubbles (sprayed out). This may indicate excessive intake of alcohol and/or recreational drugs.


I hope you will now take notice of the toilet's contents with a view to checking out whether you are healthy or not, and if you should be adjusting your diet in any way. Especially look out for blood (mainly old blood) in your poop, as this can indicate bowel or colon cancer, and is best caught early. Do not panic too much over red blood in stools, as this can simply be hemorrhoids, but it is worth getting checked out.

You might find this Bristol Stool Scale iPhone app useful if you want to download it. Over time it creates a graph of your stool quality which you can share with your health professional. This could help in monitoring the effects of lifestyle or drug changes, medical treatments, etc, over time. The app also includes links to some online resources and a brief explanation of each type.

Disclaimer: As with any online advice, this article is not meant to replace a consultation with a professional doctor, and if you are concerned about your bowel movements or your stools in general, then my advice would always be to make an appointment with a doctor as soon as you can.

Sources Used

  1. Nall, Rachel, RN, BSN. Medically Reviewed by George Krucik, MD, MBA. "Change In Bowel Habits." May 7, 2015. HealthLine. Accessed April 21, 2017.
  2. Holland, Kimberly. Medically Reviewed by Judith Marcin, MD. "Why Is There Mucus In My Stool?" August 29, 2016. HealthLine. Accessed April 21, 2017.
  3. Wilkinson, John M, MD. "Mucus in Stool: A Concern?" June 17, 2015. HealthLine. Accessed April 21, 2017.
  4. Penner, Robert M , BSc, MD, FRCPC, MSc and Sumit R Majumdar, MD, MPH. "Patient Education: Blood in the Stool (Rectal Bleeding) in Adults (Beyond the Basics)" September 3, 2015. UpToDate. Accessed April 21, 2017.
  5. Medically Reviewed by George Krucik, MD, MBA. "What Causes Floating Stools? 7 Possible Conditions." July 5, 2016. HealthLine. Accessed April 21, 2017.
  6. McDermott, Annette. Medically Reviewed by Graham Rogers, MD. "Why Is My Poop Stringy?" March 31, 2016. HealthLine. Accessed April 21, 2017.
  7. Kahn, April. Medically Reviewed by George Krucik, MD, MBA. "What Causes Foul-Smelling Stool? 7 Possible Conditions." April 14, 2016. HealthLine. Accessed April 21, 2017.
  8. Picco, Michael F, MD. "Stool Color: When to Worry." October 6, 2016. Mayo Clinic. Accessed April 21, 2017.
  9. Wilson, Dodd. "Chapter 85: Hematemesis, Melena, and Hematochezia" from Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. 1990. Butterworth Publishers. Accessed April 21, 2017.
  10. Reviewed by Arefa Cassoobhoy, MD, MPH. "What Kind of Poop Do I Have?" September 17, 2015. WebMD. Accessed April 21, 2017.


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  • mistyhorizon2003 profile image

    Cindy Lawson 5 years ago from Guernsey (Channel Islands)

    Closing comments on this article (at least for the time being) as I need to focus on other projects. Hopefully this article has helped with your problems, and if not the articles I created that cover the many colours of stools and what they mean (linked to at the end of the article itself) will be able to offer more help. If this or my other articles have not answered your questions please see your Doctor for further help.

    Good Luck.

  • mistyhorizon2003 profile image

    Cindy Lawson 5 years ago from Guernsey (Channel Islands)

    I don't know the answer to this if you specifically have GI problems as a person Beau, but am guessing your Doctor can answer this for you. Wish I could give more information, but I am not a Doctor and can't say if your stool colours will keep changing as a result of this condition.

  • profile image

    Beau 5 years ago

    Haven't been eating leafy greens but have been eating green beens alot and coleslaw. I had an ultrasound on my upper abdomen and they say it looks normal and "unremarkable" when looking at my gallbladder liver bileduct and pancreas. And I just wanted to know if there should be consistency in my stool color? Or will my stool persistently be one way or another if I have GI problems?

  • mistyhorizon2003 profile image

    Cindy Lawson 5 years ago from Guernsey (Channel Islands)

    I would advise you read each of my articles about the various meanings behind different coloured stools, (links are at the end of the article). You should largely know from the information in those articles as to what is likely to be a possible cause in your case, e.g. if it because you have been on iron supplements or have been eating a lot of blueberries, leafy green veg etc. If you can say 'ahhh yes, I have been eating those things' then you know there is little point in going to your Doctor.

    If on the other hand you can rule out all the apparent 'safe' reasons for the odd colour of your stools, and you are having the pains you describe then that is the time I would speak to your Doctor.

  • profile image

    Beau 5 years ago

    I have been looking at my stools for a long time now and I compare them all to these web sites because I am concerned that going from light brown to green to dark brown to even orangeish brown colors. All the info given here is very informative but what I want to know is when to worry and when to advise my doctor of my concerns. I mean my stool just went from orangish brown to yellowish brown to a nice brown to a dark green to a dark brown now and allover a couple weeks! All colors of which have lasted a couple days! Now I have to start taking steroids and nerve pills and muscle relaxers for a chronic lower back problem that I am getting an MRI on next week and I am just wondering what these mess are going to do to my poop! I am always watching this because my grandfather died of colon cancer and my mom died of pancreatic cancer. I go to doctor when I am not feeling well but as for any digestive issues go I eat just fine and I don't or rarely have diarea. But man this pain in my back and lower left side sucks! I am always tired and I take my hypothyroidism meds properly. I am always scared I got pancreatic cancer or something.

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