What Causes Mucus in the Bowel Movement?

Mucus is a substance that is widely produced through most parts of the body and particularly within cavities where it mainly serves as a lubricant. It is a translucent, jelly-like substance and produced in every part of the gut. It is therefore not uncommon for mucus that is produced by mucous glands that line the small and large intestine to appear in the stool. Most of the time it is never noticed but when excessive it may appear as a slimy and stringy substance coating the stool.

Mucus in Otherwise Normal Bowel Movements

A certain amount of mucus is present in normal stools of healthy persons. In fact part of the reason that normal stool is semi-soft is due to mucus, as well as water and fiber. However, when there is excessive amounts of mucus which is noticeable in other normal stool consistency then it could be due to one or more of the following conditions.


Internal hemorrhoids are a common cause of mucus in the stool. The mucus may be seen to be coating the stool and noticed when wiping after a bowel movement. Other typical symptoms of hemorrhoids includes:

Intestinal Parasites

Intestinal parasites, like giardia or intestinal worms, may cause mucus in the stools and sometimes this may be the only symptom. Other symptoms may include:

Diagnosis. Stool test shows parasites, their parts, or their ova. Blood test shows increased eosinophils and IgE antibodies.

Small Intestinal or Colonic Polyps or Colorectal Cancer

Mucus in stools may be sometimes the only symptoms of small or large intestinal polyps or cancer.

Mucus in Constipation

Mucus in hard stools may be due to:

  • Constipation due to a sedentary lifestyle, insufficient water intake, medication that causes constipation as a side effect, low-fiber diet, anxiety or depression and several other known and unknown causes.
  • Bowel obstruction from a polyp, cancer, volvulus, intussusception, or swallowed foreign object. It can also occur when movement through a section of the bowel ceases which is known as pseudo-obstruction.

Mucous Diarrhea

Irritable Bowel Syndrome (IBS)

In many cases, the cause of mucus in stools (with diarrhea or constipation) occurs where no underlying disorder can be identified. In these cases the abnormal bowel habit, often accompanied by abdominal pain, is diagnosed as IBS (irritable bowel syndrome) which was previously referred to as spastic colon. IBS is considered to be caused by an abnormality in movement through the bowels but is not due to any disease. Acute flareups may occur with psychological stress and certain irritant/trigger foods.

Read more on foods to avoid in IBS.

Food Poisoning

In food poisoning (due to bacteria or parasites), there is nausea, vomiting and diarrhea with occasional mucus stools as well as the following:

  • History of suspicious food eaten in previous 72 hours, especially where other people who had eaten the same foods are also affected.
  • Bloating, abdominal cramps, occasional fever or, rarely blood in the stool.

Mucus and greenish diarrhea is common with infections caused by the giardia parasite that leads to giardiasis.

Food Intolerances

The term ‘food intolerance’ is a broad term that refers to conditions where the body cannot digest or absorb certain nutrients. It may also be incorrectly used to describe cases where foods trigger inflammation due to an immune-mediated allergu response. Therefore in these cases mucus often appears in stool due to:

Diagnosis is primarily reached through an elimination diet whereby foods are removed from the diet one at a time and then gradually reintroduced. The other diagnostic method that may be considered is a breath test.

Small Intestinal Bacterial Overgrowth (SIBO)

Bacteria may overgrow in small intestine in various conditions fructose malabsorption, diabetes, systemic sclerosis, and other disorders with impaired gut motility. Normally bacteria is not found in large quantities within the small intestine, if at all. When these bacteria enter the small intestine, it may proliferate without any controlling measures that limit its population size. This is an overgrowth and not an infection.

Read more about SIBO.

Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease is a chronic condition where there in inflammation of the wall of the gut and particularly in the large intestine. There are two types – Crohn’s disease and ulcerative colitis. In Crohn’s disease (especially when anal fissure or pelvic abscess are present), and ulcerative colitis, mucus in bowel movements (with or without diarrhea) is common. Other common findings in IBD:

Diagnosis of IBD is made by colonoscopy and a biopsy of the colonic mucosa.


In diverticulitis, inflamed (usually infected) pouches appear in colon which is mainly due to long term straining at defecation in constipated people. It is more common in older people. Beside mucus, other symptoms include:

Pancreatic Disease

The pancrease secretes water, mucus, digestive enzymes and electrolytes into the duodenum (small intestine). Mucus in the stool may appear in the following pancreatic disorders:

  • Papillary-mucinous tumor (rare)

In pancreatic disease there may be a problem with fat-digesting enzymes known as lipases. This may prevent fat digestion and the fats then pass out with stool. Fatty stool is known as steatorrhea and may be mistaken for mucus in the stools.

Cystic Fibrosis

Cystic fibrosis is a genetic disease, where salivary, bronchial, sweat, intestinal glands, and pancreas secrete excessive amount of dense mucus. Symptoms include:

  • Mucous diarrhea from birth
  • Coughing mucus
  • Repeating respiratory or other infections

Diagnosis is made by a sweat test that shows increased amount of salt in the sweat.

Short Bowel Syndrome (SBS)

After surgery, where a considerable amount of small intestine was removed, mucous diarrhea may appear  and persist for long periods, especially in small children. More about short bowel syndrome.

Related Articles:

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  • Dr. Chris

    Hi Dominique

    Yes, hemorrhoids could account for many of the symptoms you are now experiencing including the mucus. However, you should see your doctor to investigate proctitis which could be related to a sexually transmitted infection. Prompt diagnosis and treatment can help minimize any complications. Your doctor will be able to advise your further.

  • Shaheed

    I am 17 years old , and I have been pooping mucus
    What could be the problem

  • Hi Shaheed. As you can see above there are many possible causes. It depends on what other symptoms are present. Hemorrhoids is one of the more common causes for small amounts of mucus in the stool. Inflammatory bowel disease may be another relatively common cause. The accompanying symptoms like diarrhea, anal itching and so on can be helpful in identifying the most likely condition.

  • Joe smith

    I’m 47 years old and I’ve ben losing weight for about 2 to 3 years. I’ve had constipation for that whole time. I haven’t paid any attention to my stool at the time, but the last 5 months I noticed what looks like white worms in my stool. If left in toilet for about a hour, it seems to dissolve to look like mucus. Symptoms that may or may not be related are itchy skin, muscle pain, and a small balance problem. I could use some help identifying this problem.

  • Hi Joe. Most of these symptoms are present in a number of different conditions so the question is whether this is a single condition or multiple conditions. Some diseases can affect multiple systems simultaneously, like diabetes, HIV infection, autoimmune diseases and so on. The simultaneous weight loss is a cause for concern especially with constipation and mucus in the stool. These days one has to be attentive for early signs of conditions like colorectal cancer but do not be too concerned just yet. Rather see your doctor and have this checked up.

  • Iggy

    I’m 24, and about two months ago I started pooping mucus. It went on for 3 days and then stopped. Then a month later it started again but only happened twice, and it happened again just today, so it’s infrequent. All other bowel movements are normal. The mucus will occassionally have some red flecks in it, but otherwise it’s clear. When I pass this mucus I have an intense urge to go to the bathroom, but it’s not painful, and when I go, it’s nothing but this small mucus lump and nothing else. What could be wrong?

  • Hi Iggy. There may be several reasons for mucus in the stool as you can see from the article above but one of the concerns in your age group is inflammatory bowel disease (IBD). It must not be confused with irritable bowel syndrome (IBS). You need to see a doctor as soon as possible and possibly undergo further investigations like a colonoscopy. While your symptoms may not be severe right now, IBD is a serious condition and sometimes may hold significant risks as your doctor will explain to you. However, with early diagnosis and proper treatment it can be managed well. Of course there could be other conditions causing this symptom so your doctor will advise your further.

  • Allergy parent

    Thank you for the helpful information. I suspect my 18 month old’s pale yellow, runny, mucousy poops from the last 2 days are caused by the same bug that had him throwing up several times the day before they started but I’ll be sure to take him to the doctor if they persist beyond another day or 2.

    I do have a complaint about the article, however, that would be easily corrected. Under the large topic heading of Mucous Diarrhea there are several subheadings, including Irritable Bowel Syndrome, Food Poisoning, and “Food Intolerances.” By listing food in tolerances in quotes, when none of the other subheadings are, this article gives the impression that the things in that category, which include food allergies and Celiac disease, are imaginary or not something to take seriously. I am sure your site does not intend to give that impression since both conditions are very serious and food allergy in particular, is often life threatening. People with these conditions spend a lot of time trying to convince those around them to take their conditions seriously, they do not need educational sites such as this fighting against them.

  • Hi Allergy Parent. Thank you for bringing that to our attention. We are definitely not inferring that food intolerances are imaginary conditions. Food intolerances are very real conditions. However, as you may have noted the article discussed both intolerances and malabsorption syndromes as well as food allergies. So the food intolerance in quotes is being used as an umbrella term. For example lactose intolerance is a food intolerance where the body cannot digest lactose. Fructose malabsorption is not a problem with digestion but rather with absorption. Celiac disease is a reaction to gluten. So an allergy or malabsorption is not a food intolerance like lactose intolerance but people find that they cannot tolerate these foods for the other reasons mentioned. Hence we used the quotes to say that while you may find that you cannot tolerate certain foods its not always a typical food intolerance as we would look at lactose intolerance. Hope that clarifies the issue.

  • Tanja

    Help.. Ok about a yr ago i was so constipated i did not have a BM for nearly a month. I went to ER they acted like i was lyin gave me an enema amx sent me home. Then 3 months later mucus in my stools, a little at first then there was nothing but mucus and blood. I had/have stomach pain all the time, have to force a bm and still its mainly mucus. In 6 months i went from heavier 210 (im 6ft) to 160.. I couldn’t eat. It made me hurt, nausea then i start belching. Huge gross belchess all the time.. Now here i am a yr later i weigh 169 im pale always cold, cant eat much, still constipation mucus and bloody stools.