What causes mucous diarrhea?

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Last updated: April 12, 2025View editorial policy

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From the Guidelines

Mucous diarrhea can be caused by several conditions, including inflammatory bowel diseases, infections, irritable bowel syndrome, food intolerances, and certain medications, with the most recent evidence suggesting that microscopic colitis, particularly collagenous colitis and lymphocytic colitis, are distinct clinicopathologic entities that can present with chronic watery diarrhea 1.

Causes of Mucous Diarrhea

  • Inflammatory bowel diseases: Crohn's disease and ulcerative colitis can trigger inflammation and excess mucus production in the digestive tract.
  • Infections: bacterial dysentery (Shigella), Salmonella, Campylobacter, and parasitic infections like Giardia can lead to mucous diarrhea.
  • Irritable bowel syndrome (IBS): frequently presents with mucus in stool, particularly in IBS with diarrhea predominance.
  • Food intolerances or allergies: may trigger intestinal inflammation resulting in mucous diarrhea.
  • Certain medications: particularly antibiotics that disrupt gut flora, can cause this symptom.
  • Microscopic colitis: a distinct clinicopathologic entity characterized by chronic watery diarrhea, with two major entities known as lymphocytic colitis (LC) and collagenous colitis (CC) 1.

Diagnosis and Treatment

  • Diagnosis depends on identifying the underlying cause, which may require stool tests, colonoscopy, or other diagnostic procedures.
  • Treatment depends on the underlying cause, and may involve staying hydrated, avoiding trigger foods, and taking medications to manage symptoms.
  • If mucous diarrhea persists beyond a few days, is accompanied by fever, severe abdominal pain, or blood, medical attention should be sought promptly.

Recent Evidence

  • A study published in 2013 in the Journal of Crohn's and Colitis found that microscopic colitis is a distinct clinicopathologic entity characterized by chronic watery diarrhea, with two major entities known as lymphocytic colitis (LC) and collagenous colitis (CC) 1.
  • The study also found that the diagnosis of collagenous colitis is based on the presence of a thick amorphous hyaline eosinophilic band immediately beneath the surface epithelium of the mucosa, with a thickness of ≥ 10 μm 1.

From the Research

Causes of Mucous Diarrhea

  • Giardiasis, an infection caused by the protozoan parasite Giardia lamblia, can lead to diarrheal illness, including mucous diarrhea 2, 3.
  • Post-giardiasis irritable bowel syndrome (IBS) may also cause mucous diarrhea, although the exact mechanisms are not fully understood 4.
  • Intestinal malabsorption of fat and carbohydrates may play a role in the development of mucous diarrhea in patients with post-giardiasis IBS 4.
  • Other factors, such as low-grade inflammation in the intestine, may contribute to the development of mucous diarrhea in patients with IBS 5.

Associated Conditions

  • Giardiasis can cause a range of symptoms, including diarrhea, weight loss, and malabsorption 2, 6, 3.
  • IBS can cause abdominal pain, changes in bowel habits, and stool frequency, in addition to mucous diarrhea 4, 5.
  • Post-giardiasis IBS can be resistant to treatment and may require alternative therapies, such as antibiotics or bacteriotherapy 4.

Treatment Options

  • Metronidazole, tinidazole, and nitazoxanide are commonly used to treat giardiasis, although resistance to these drugs is increasing 2, 6, 3.
  • Mesalamine, an anti-inflammatory drug, may be effective in treating IBS with diarrhea, including mucous diarrhea 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Treatment of giardiasis.

Clinical microbiology reviews, 2001

Research

Giardiasis: An Overview.

Recent patents on inflammation & allergy drug discovery, 2019

Research

Antibiotic or bacterial therapy in post-giardiasis irritable bowel syndrome.

Scandinavian journal of gastroenterology, 2009

Research

Systematic Review and Meta-analysis: Efficacy of Mesalamine in Irritable Bowel Syndrome.

Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association, 2024

Research

Drugs for treating giardiasis.

The Cochrane database of systematic reviews, 2012

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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