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Last updated on
3 min read

Key takeaways

Mucus in the stool is a viscous substance that lubricates feces to pass through the intestinal tract.

  • A large quantity or frequent recurrence of mucus in the stool is uncommon for dogs warranting non urgent veterinary investigation
  • Mucus in the stool has a variety of causes, the most common being colitis
  • Diagnosing mucus in the stool may involve a number of physical exams, as well as a fecal exam
  • Treatment of this symptom depends on the underlying condition and may include dietary changes, anti-parasitics, anti-inflammatories, or antibiotics
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A closer look: Mucus in the Stool in Dogs

Mucus is one of the body’s natural lubricants. In dogs, it eases the passage of stool from the body. Healthy dogs occasionally secrete small amounts of mucus in feces. A large amount of mucus over a number of days is uncommon and may indicate colitis (inflammation of the colon), intestinal parasites, or other more serious conditions such as cancer.

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Possible causes

Mucus in the stool can be caused by any condition that causes inflammation in the bowel.

Risk factors

The severity of mucus in the stool does not correlate to the severity of disease. However, the location of the mucus in the feces may help identify the area of concern. For example, mucus surrounding the stool often indicates a lower bowel condition (such as colitis) compared to mucus within the stool.

While this symptom may pass in just a few days, elderly dogs, puppies, and dogs with pre-existing conditions are at higher risk of more serious illness. Dogs in this group benefit from prompt veterinary assessment if changes in the stool persist.

If large amounts of mucus in the stool are accompanied by symptoms such as vomiting, bloody stool, collapse, lethargy, or abdominal pain, urgent veterinary attention is needed.

Testing and diagnosis

Methods of diagnosing mucus in the stool include:

  • Physical exams
  • Rectal exam
  • Fecal exam

Identifying potential underlying conditions causing mucus in the stool include:

  • Endoscopy
  • Abdominal x-rays and ultrasound
  • Biopsy
  • Bloodwork

Following diagnosis, the treatment depends on the underlying cause and can include:

  • Anti-parasitics
  • Diet changes
  • Stress relief
  • Antibiotics
  • Anti-inflammatories
  • Anti-nausea medication
  • Fluid therapy
  • Immunosuppressive medications
  • Surgery
  • Chemotherapy and radiation (if cancer)

Similar symptoms

Mucus in the stool is unlikely to be mistaken for any other substance. It may appear similar to mature tapeworms, but is visually distinct.

Associated symptoms


Dr. Rebecca MacMillan - Writing for The Vets
Jennifer Coates, DVM - Writing for PetMD

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