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Top 8 Causes of Mucus in Stool

Mucus in stool is normal but when you see a lot of white or yellowish mucus, it means you may have a GI problem, like a stomach bug, IBS, inflammatory bowel disease, celiac, or other issue. It’s important to make sure something in your diet isn’t causing it and see a doctor to look for an underlying intestinal issue.
Two brown pieces of stool with green splotches in a green puddle.
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Written by Shria Kumar, MD.
Therapeutic Endoscopy Fellow, MD Anderson Cancer Center, Houston, TX
Last updated May 3, 2024

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We all have mucus in our stool to aid in the natural digestive process. It’s a lubricant that helps food pass from the mouth to the stomach. Mucus is crucial to helping the colon and intestines function properly. Mucus produced by glands in the rectum also helps expel stool. So it’s not unusual for your stool to contain mucus.

But if you notice an unusual amount, it might be a sign of something else: infection, irritable bowel syndrome, inflammatory bowel disease (IBD), celiac disease, anal or rectal issues, or even cancer.

1. Irritable bowel syndrome (IBS)


Irritable bowel syndrome (IBS) is a common, chronic disorder of the gut. It can cause abdominal pain and changes in your bowel movements. These are usually worse when the person is stressed, eats certain foods, recovering from stomach bugs, or, for women, at specific times during their menstrual cycle.

People with IBS are more likely to have other disorders, such as fibromyalgia, chronic fatigue syndrome, chronic pelvic pain, or temporomandibular joint disorder (TMJ). Though these are “benign” (i.e., not cancerous and not a serious threat to physical health), IBS can greatly impact quality of life.

Treatment is aimed at relieving the various symptoms, such as taking antispasmodics for cramps, and anti-diarrheal medication. It may also include cognitive behavioral therapy to help reduce stressors.

Read more about IBS.

2. Lactose intolerance


Lactose intolerance is when you cannot digest lactose, the main carbohydrate in dairy products (e.g., milk, cheese, ice cream). People with lactose intolerance don't make enough of the enzyme lactase, which is needed to digest lactose. Symptoms occur after consuming dairy products, usually within 8 hours.

Lactose intolerance can happen due to genetics, with older age, or after an intestinal infection. Treatment involves avoiding lactose-containing products or taking a lactase supplement while eating dairy foods.

Read more about lactose intolerance.

3. GI infections


  • Diarrhea
  • Stomach pain
  • Bleeding

Infections of the gastrointestinal (GI) tract can be due to viruses, bacteria, or parasites. You can get them from eating contaminated food or drinking contaminated water, or from poor hand hygiene.

Treatment involves staying hydrated and letting the bowel rest (by eating bland foods). If you have a bacterial or parasitic infection, you may take an antibiotic or anti-parasitic medication.

4. Inflammatory bowel disease (ulcerative colitis or Crohn’s disease)


Inflammatory bowel disease (IBD) is an inflammation of the intestines caused by abnormal immune system activity. There are two types of IBD: ulcerative colitis (UC) and Crohn’s disease (CD). Both can come and go. When the disease flares up, the lining of your intestines becomes inflamed and causes symptoms.

Treatment involves tamping down inflammation (with steroids, topical agents, or biologic agents).

Read more about inflammatory bowel disease.

What causes mucousy stool?

Our GI tract is very complex. When your bowel habits or movements change, it’s an indication something is going on. That something may be benign (something you ate, not drinking enough water) or something more insidious (cancer, inflammatory bowel disease).” —Dr. Shria Kumar

5. Celiac disease


Celiac disease is an autoimmune response in the gut to gluten, which is a protein in wheat, rye, and barley. Eating gluten can cause damage to the lining of your small intestine.

This causes bloating and diarrhea and can result in not being able to absorb nutrients. When this happens, most people lose weight, feel fatigued, and develop fragile bones, severe skin rashes, mouth ulcers, and anemia.

Celiac disease is diagnosed through blood testing and endoscopy.

The treatment is to avoid eating gluten. Doctors may also check that you are absorbing vitamins. They do this by testing blood levels to ensure nutrient levels are normal. They also keep an eye on bone health (by blood markers and bone scans) to make sure vitamin D is being absorbed.

Read more about celiac disease.

6. Anal fissures


  • Pain when passing a bowel movement
  • Bleeding

Anal fissures are tears in the lining of the anus. They occur due to passing of hard bowel movements. Many fissures heal on their own, but there are medications you can apply to the tears that may speed up the healing and reduce pain.

Ensuring soft bowel movements is also crucial to preventing and treating anal fissures. This can be done by drinking enough water, having a balanced diet, and if needed, using stool softeners.

Read more about anal fissures.

7. Gastrointestinal (GI) cancers


  • Weight loss
  • Change in bowel habits
  • Changes in diets
  • Bleeding
  • Fatigue

Gastrointestinal (GI) cancers can happen anywhere in the digestive tract (in the esophagus, stomach, small intestine, colon, or rectum). Since they disrupt normal GI functioning, they can lead to a variety of symptoms, including mucousy stool. If you are experiencing any unusual or unexplained symptoms, call your doctor. Treatment can involve surgery, chemotherapy, and radiation therapy.

8. Volvulus


  • Severe abdominal pain that comes on suddenly
  • Nausea or vomiting
  • Changes in stool
  • Fevers

Volvulus is an intestinal obstruction due to twisting of the intestine. It can cause severe pain and symptoms. This will also cause changes in your bowel habits almost immediately, and mucousy stool can be a part of it.

Risk factors for volvulus include having scar tissue from prior surgeries, congenital defects, and increasing age. Treatment involves a colonoscopy and/or surgery to “untwist” the intestine.

What should I ask my doctor when I have loose mucus stool?

“Two questions to ask your doctor: What caused this? Do I have to change anything?” —Dr. Kumar

When to call the doctor

Contact your primary care doctor, if you have mucousy stool plus any of the following:

  • Severe abdominal pain
  • Bleeding
  • Prolonged periods of constipation or diarrhea
  • Fever
  • Nausea or vomiting

Should I go to the ER for mucousy stool?

You should go to the ER or seek immediate medical care if your mucousy stool is accompanied by any of the following:

  • Bleeding
  • Lightheadedness, dizziness, feeling faint
  • Fever
  • Severe abdominal pain
  • Inability to eat or drink
  • Confusion

What does mucousy stool mean?

“Mucousy stool on its own is not a problem, it’s a symptom. So if it’s a one-time thing, as your doctor, I would not be worried. If you go from regular soft bowel movements without mucous to a change in bowel movements and the presence of mucous, I would be more concerned.”—Dr. Kumar


At-home care

When the mucousy stool is just related to diet or a recent infection (most cases), it requires no treatment. It’s good practice to monitor your diet, and make sure you are having regular, soft bowel movements:


  • Eating a healthy, balanced diet to promote positive digestion and minimize mucus in stools.
  • Avoid fatty foods.
  • Limit dairy.
  • Drink a lot of water.
  • Take dietary supplements such as iron, calcium, and vitamins D and B12, if you aren’t getting enough from foods.

Over-the-counter medications:

  • If you are constipated, fiber supplements or laxatives may also help promote healthy bowel movements.

Other treatment options

Prescription medications

  • If your mucousy stool is due to an infection (diagnosed via stool test), your doctor may prescribe antibiotics.
  • If your mucousy stool is due to inflammatory bowel disease (diagnosed via colonoscopy and imaging), your doctor may prescribe medication for it.
  • Fiber Supplements: If constipation is a contributing factor to your mucousy stools, adding fiber to your diet can help. Products like psyllium husk can be effective.
  • Probiotics: For general intestinal health or mild cases of GI infections, probiotics can promote a balanced gut flora.
  • Lactase Enzymes: If lactose intolerance is causing your symptoms, lactase enzyme supplements can help you digest dairy products more comfortably.
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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Therapeutic Endoscopy Fellow, MD Anderson Cancer Center, Houston, TX
Dr. Kumar is a gastroenterologist, who completed her fellowship at the Hospital of the University of Pennsylvania in Philadelphia. She received her undergraduate degrees in Religious Studies and Chemistry from New York University (2010) and graduated from the Albert Einstein College of Medicine (2014), where she was inducted into the Alpha Omega Alpha Honor Medical Society. She is completing her t...
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