Small amounts of mucus in the stool is normal. However, larger amounts of mucus in their stool may indicate inflammatory bowel disease (IBD) or other medical conditions.

Mucus in the gut is crucial for helping to maintain a person’s gut health. The mucus can defend against bacteria, digestive enzymes and acids, and other toxins to maintain a stable environment in the gut. It also acts as a natural lubricant and helps the stool to pass.

However, problems with the mucus barrier in the intestines can result in inflammation and contribute to the development of IBD. Mucus in the stool is a main symptom of IBD.

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According to research from 2019, it is normal for a small amount of mucus to be present in stool. The mucous membrane of the large intestine helps the stool to pass.

A typical bowel movement will not produce much mucus. It may be tawny or clear in color, and a person is unlikely to notice it.

When stool has visible mucus, it can be a sign of other health conditions, such as an infection, irritable bowel syndrome (IBS), ulcerative colitis (UC), or Crohn’s disease.

Other signs to look for:

  • increased amounts of mucus
  • blood or pus in the stool
  • stomach pain, cramping, or bloating
  • sudden changes in stool frequency, consistency, or color

A person should contact a doctor if they notice mucus in their stool.

Possible causes of mucus in stool include:

Crohn’s disease

Crohn’s disease is a long-term condition that causes inflammation in the digestive tract, which runs from the mouth to the anus. It is a form of IBD.

Those with Crohn’s may notice mucus, pus, or blood in their stool.

Other symptoms of Crohn’s include:

  • persistent diarrhea
  • rectal bleeding
  • abdominal cramps
  • abdominal pain
  • constipation
  • urgent need to have a bowel movement
  • the feeling of an incomplete bowel evacuation

Ulcerative colitis (UC)

UC is another form of IBD. It occurs due to an overactive reaction of the immune system. It can flare up, or be active, at times and be inactive at other times.

During a flare-up, the mucous membrane of the large intestine becomes inflamed and develops ulcers. These ulcers can bleed and produce pus and mucus.

Other symptoms of UC include:

  • urgent and loose bowel movements
  • blood in the stool
  • abdominal cramps and pain
  • persistent diarrhea

Irritable bowel syndrome (IBS)

People living with IBS may notice whitish mucus in their stool.

Other common symptoms of IBS include abdominal pain and changes in bowel movements, such as constipation and diarrhea. People living with IBS may also experience other symptoms, such as bloating and the sensation that a person has not finished the bowel movement.

Proctitis

Proctitis is inflammation of the lining of the rectum that can be short-term or long-lasting. The most common symptom is having a frequent and urgent need to have a bowel movement.

Another symptom of proctitis is mucus or pus discharge from the rectum, which a person should report to a doctor right away.

Other symptoms include:

  • a feeling of fullness in the rectum
  • rectal pain
  • abdominal cramping
  • pain during bowel movements
  • rectal bleeding
  • diarrhea
  • constipation
  • swollen lymph nodes in the groin

Intestinal infection

Infection in the gastrointestinal (GI) tract might also cause mucus in the stool. Infections can occur as a result of bacteria, viruses, or parasites. For example, dysentery is an intestinal infection that can occur due to bacterial or parasitic infection and can lead to diarrhea containing blood or mucus.

Other symptoms may include:

Read on to learn more about gastrointestinal infections and infectious colitis.

Colorectal cancer

Colorectal cancer refers to cancer of the colon or rectum, which are part of the digestive tract.

Colon cancer begins in the mucosa, the inner layer of the bowel wall, which contains mucus-producing cells called goblet cells. People with colon cancer might see mucus streaked with blood in their stools.

Other symptoms include:

  • change in bowel habits that lasts for more than a few days
  • constipation or incomplete bowel evacuation
  • dark brown or black stool as a result of blood
  • bright red blood in the stool
  • cramping in the abdomen
  • weakness
  • fatigue
  • weight loss

Mucus in the stool may have other causes.

These can include:

  • celiac disease, otherwise known as gluten intolerance
  • lack of dietary fiber, which is needed to bulk out stool and help move waste smoothly out of the body
  • intestinal parasites, such as tapeworms, hookworms, and pinworms
  • cystic fibrosis, a genetic disorder that causes an excess of mucus in the intestines and other organs

Usually, the first step toward understanding what is causing mucus in the stool is to test a stool sample.

A healthcare professional will give instructions on how to take a sample. It usually involves collecting a stool sample in a clean container and, if a person is unable to hand it in immediately, storing it in the fridge to prevent bacteria from building up.

Once a healthcare professional has the sample, they can test it for bacteria and other substances from the digestive system.

Depending on the stool sample results, a person may need further tests to investigate the cause of excess mucus in the stool. These tests may include:

  • blood tests
  • endoscopy, which involves inserting a thin, flexible tube with a camera and light on the end, through the mouth or into the rectum
  • colonoscopy, which is a type of endoscopy that examines the lower part of the digestive tract
  • imaging tests, such as CT scan, ultrasound, and MRI scan

It is normal for a small amount of mucus to be present in the stool. If a person regularly notices excess mucus or other changes in bowel movements, they should talk with a doctor.

If mucus in the stool happens alongside other symptoms, it could be a sign of a condition that requires investigation and treatment.

A person should contact a doctor if they experience:

  • persistent diarrhea
  • abdominal pain
  • blood in the stool
  • vomiting
  • unexplained fatigue
  • unexplained weight loss

To help a doctor diagnose the issue, a person should keep a record of their bowel movements and any other symptoms. Keeping a food journal might also help identify food-related conditions.

Treatment will depend on the results of diagnostic tests.

If mucus in the stool is related to diet, a doctor might recommend drinking more water or increasing fiber intake.

Treatment might include prescription medication and lifestyle changes for long-term conditions such as Crohn’s, UC, and IBS.

If doctors diagnose cancer, they will refer a person to an oncologist, a specialist cancer doctor, who will devise a treatment plan specifically for them.

Rectal discharge can occur for many reasons. In some cases, it can be a sign of an underlying problem. Possible causes may include IBD, IBS, infection, cancer, rectal prolapse, an abscess, a fistula, or hemorroids.

When a person is generally healthy, mucus in stool is typically clear. However, in some people it may be more white or yellow.

Mucus appearing in stool is a possible symptom of IBS. As such, when a person experiecing IBS passes a stool, they may notice stringy mucus covering their stool.

Having a small amount of mucus in the stool is normal.

Excess mucus can occur due to IBS, Crohn’s, UC, or proctitis. It may also be an indication of colon cancer.

If a person is concerned about the amount of mucus in their stool or experiences other symptoms, they should talk with a doctor.