Mucus, a translucent, jelly like substance that appears in the stool is produced by mucous glands that line the small and large intestine.
Mucus in Otherwise Normal Bowel Movements
Certain amount of mucus is regularly present in normal stools in healthy persons. Mucus in normal semi-soft stools may appear in bellow conditions:
Internal hemorrhoids are common cause of mucus in the stool. Mucus is usually not mixed with the stool. Other typical symptoms in hemorrhoids are:
Intestinal parasites, like giardia or intestinal worms, may appear with mucus in stools as the only symptom. Other symptoms may include:
- Chronic bloating
- Chronic diarrhea
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 in small or large intestinal polyps or cancer.
Mucus in Constipation
Mucus in hard stools may be due to:
- Constipation due to inactivity, insufficient water intake, medications, low-fiber diet, anxiety, depression or other causes
- Bowel obstruction from a polyp, cancer, volvulus, intussusception, or swallowed foreign object
Irritable Bowel Syndrome (IBS)
In many cases, the cause of mucus in stools (or diarrhea) no underlying disorder can be identified, and a diagnosis of an IBS is given to affected person. IBS is considered to be caused by stress and irritating foods. Foods to avoid in IBS.
In food poisoning (due to bacteria or parasites), besides diarrhea and occasional mucus, the following is common:
- History of suspicious food eaten in previous 72 hours; other persons who had eating the same food are affected
- Bloating, abdominal cramps, occasional fever or, rarely, blood in the stool
Mucus and greenish diarrhea is common in infection with parasite giardia.
Mucus often appears in stool in:
- Fructose malabsorption
- Lactose intolerance (symptoms appear after dairy)
- Food allergies
- Celiac disease (symptoms appear after eating gluten containing cereals: wheat, barley and rye)
Diagnosis is made by elimination diet and/or breath tests.
Small Intestinal Bacterial Overgrowth (SIBO)
Bacteria may overgrow in small intestine in fructose malabsorption, diabetes, systemic sclerosis, and other disorders with impaired gut motility. More about SIBO.
Inflammatory Bowel Disease (IBD)
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:
- Low grade fever, malaise
- Blood in the stool
- Blood test show elevated white blood cells
Diagnosis of IBD is made by colonoscopy and biopsy of colonic mucosa.
In diverticulitis, inflamed (usually infected) pouches appear in colon, mostly due to long term straining at defecation in constipated people. Beside mucus, other symptoms include:
Mucus in the stool may appear in the following pancreatic disorders:
- Papillary-mucinous tumor (rare)
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 operation, 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.