Anal and Rectal Bleeding In Cats

Causes      Additional symptoms     Diagnosis           Treatment

Anal bleeding in cats

Anal and rectal bleeding at a glance

  • Anal and rectal bleeding refers to blood from the anus, the rectum or is on the inside or outside of the feces.
  • There are a number of causes including constipation, polyps, cancer, inflammation and internal bleeding.
  • Diagnosis is based on accompanying symptoms as well as diagnostic tests including colonoscopy, medical imaging, routine blood and fecal studies.
  • Treatment depends on the underlying cause but may include surgery, stool softeners, anti-worming medications, antibiotics and dietary changes.

Anal and rectal bleeding refers to blood which may be noticed on or around the anus,  the opening at the end of the cat’s digestive tract, its function is to pass feces out of the body,  or the rectum, which is the final section of the large intestine, inside your cat.

You may notice bright red blood on the anus, especially after a bowel movement, but more commonly blood is seen on or in the feces.


Causes of anal bleeding in cats

Blood can originate internally, from the stomach and intestines (colon, rectum, anal canal) or externally, from the anus or the anal glands.

Impacted anal glands:

Located at the 5 and 7 o’clock position on the cat’s anus, the anal glands contain a thick, foul-smelling substance which is released from the glands when the cat defecates. From time to time, the substance within the glands can become thick, causing impaction and inflammation. Eventually, the glands will abscess and possibly rupture.

Symptoms include pain when defecating and the presence of blood in the feces or around the anus and an unpleasant smell.


From time to time, your cat may experience difficulty emptying his bowels. When this occurs, the feces can become dry and hardened. Small tears can occur in the rectum when a constipated cat passes a stool.

Symptoms include crying in the litter tray, passing small amounts of feces, or straining to defecate.

Rectoanal polyps:

These types of polyps are uncommon in cats. Polyps are noncancerous nodular growths in the rectum or anus.

Symptoms may include straining to defecate, blood in the stool and occasionally you may see a polyp protruding from the anus.

Hookworm infection:

Hookworms live in the small intestines of cats, they attach to the wall of the intestine, which causes the area to bleed. Symptoms of hookworms may include bloody stools which are often running, pale gums (due to anemia), and stunted growth in kittens.

Inflammatory bowel disease:

This condition is due to the infiltration of inflammatory cells into the gastrointestinal tract, resulting in inflammation. The exact cause is not known.

The most common symptoms of IBD include chronic vomiting and diarrhea, sometimes with blood in it.


Cancers can occur anywhere along the intestinal tract and rectum can lead to bleeding. There are several types of cancer which can form depending on the originating cell. These include mast cell cancer, lymphoma, adenocarcinoma, neoplasms.

Common symptoms include weight loss, vomiting, bloody diarrhea, anorexia, lethargy and abdominal mass.


Inflammation of the lining of the colon (large intestine) which have a number of causes including infection, stress, dietary, parasites or cancer.

Symptoms of colitis include diarrhea, which may contain blood, frequent passage of watery stools, reduced appetite.


Other infections which cause inflammation of the intestines, such as salmonella, cryptosporidium, and E-coli.

Blood clotting disorders:

This can include low platelets (thrombocytopenia) or coagulation factors (which cause hemophilia).

  • Most cases of hemophilia are inherited, but liver disease, aspirin poisoning, and rodenticide poisoning can also cause blood clotting disorders.
  • Thrombocytopenia has a number of causes including leukemia, myelodysplasia syndrome, viral infections, immune-mediated destruction of platelets.

Accompanying symptoms:

Additional symptoms can vary depending on the underlying cause, but may include:

  • Anal scooting, where your cat drags his bottom along the floor.
  • Difficulty defecating, spending longer than normal in the litter tray or defecating outside the litter tray.
  • Painful defecation (constipation, polyps, cancer).
  • Swelling around the anus (impacted anal glands or anal gland abscess).
  • Mucus in the stool (inflammation or infection).
  • Diarrhea (due to infection, inflammation or hookworms)
  • Blood in the urine (due to low blood platelets).
  • Pale gums due to anemia (hookworm infection)
  • Red spots on the gums (due to low blood platelets).


Your veterinarian will perform a complete physical examination of your cat and obtain a medical history from you. Depending on presenting symptoms, he will want to run some diagnostic tests to determine a cause. Tests may include:

  • Complete blood count, biochemical profile, and urinalysis to evaluate organ function, check for signs of inflammation. Cats with thrombocytopenia will have low blood platelets. Anemia may be present in cats who have severe hookworm infection.
  • X-Ray or ultrasound to look at the GI tract for tumours or polyps.
  • Colonoscopy which involves insertion of a fine tube with a camera at the end to evaluate the colon for signs of inflammation, polyps, and/or cancer. Biopsies may be taken at this time which will be evaluated.
  • Blood clotting tests for hemophilia such as coagulation assays.
  • Bone marrow biopsy to determine the cause of low blood platelets.


Treatment depends on the underlying cause and may include:

  • Impacted anal glands – Empty the glands and pack with antibiotic ointment. Your cat may need to go on a course of antibiotics. If the problem is recurrent, surgical removal of the glands.
  • Constipation – A high fibre diet or adding fibre to his diet and encouraging water consumption as well as stool softeners when needed.
  • Rectoanal polyps – Surgical removal of the polyps. They may return at a later date, requiring additional surgery.
  • Cancer – Surgery to remove the growth if possible, chemotherapy or radiotherapy may also be necessary.
  • Intestinal parasites – Worming medication to kill the parasites.
  • Inflammatory bowel disease and colitis – Management of these conditions with a highly digestible diet, corticosteroids and antibiotics when needed.
  • Salmonella and E-coli treated with antibiotics.
  • Blood clotting disorders Find and treat the underlying cause if possible. Whole blood or plasma transfusions may be necessary to maintain normal blood cell counts and administration of vitamin K.

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