Blood in Cat Stool (Hematochezia) – Bright Red Blood in Stools

Causes of blood in feces       Other symptoms to watch for      Diagnosing the cause of blood in feces      Treating blood in stool

Blood in cat stool at a glance

  • Blood may be bright red (hematochezia), or dark and tarry (melena).
  • Bright red blood is associated with the lower intestine, colon, and anus and is more obvious than melena.
  • Dark tarry stools are associated with upper GI tract bleeding, the blood you see here has been digested.
  • Common causes include polyps, anal gland rupture, parasites, infection, constipation, colitis, poisoning, blood clotting disorders and cancer.

blood in cat stool

It is always alarming when we discover blood in your cat’s stool but in a lot of cases, the cause is minor and transient. Blood in the cat’s stool may be light, with just a smear or speck or heavy and it may be with or without accompanying symptoms.

The presence of blood in the stool can be broken into two types:

  • Melena – Tarry black stools are associated with upper gastrointestinal tract bleeding including the esophagus, stomach, and duodenum but bleeding may also originate from the nose or mouth. This blood has been broken down by naturally occurring bacteria in the stomach before passing out down the lower intestinal tract and out of the anus.
  • Hematochezia – Bright red blood which is associated with lower intestinal (colon and rectum) and anal bleeding. This type of blood in the stool is much more obvious than melena. It may be throughout the feces or just on the outside.

This article focuses on bright red blood in the stool.

What are the causes of blood in your cat’s stool?

The occasional sighting of bright blood in the feces is usually insignificant, however, if it lasts longer than a day if there is a large volume of blood passed and/or if other symptoms are also present it is something which needs to be investigated as soon as possible.  There are many possible causes of blood in the cat’s feces, some of which include:

Parasitic infection (cryptosporidiumintestinal worms) Cryptosporidium causes inflammation which leads to bleeding, parasitic worms such as hookworm or roundworms suck the blood from the intestinal wall, resulting in blood in the stool. Parasites are one of the most common causes of blood in stool in kittens.
Bacterial infection Bacterial infection, salmonella, campylobacter and e.coli.
Viral infection Panleukopenia is a highly infectious viral infection which affects the white blood cells. Kittens are most at risk of this disease. Symptoms can include loss of appetite, listlessness, vomiting, bloody diarrhea, and dehydration.
Constipation Difficulty passing feces. Hard, dry stools can cause irritation and/or minor tears in the bowel and anus.
Impacted and/or inflamed anal glands  The anal glands are two small sacs on either side of the anus when the cat defecates, the glands release a thick, foul smelling substance. Sometimes these glands become impacted and inflamed, leading to infection and/or an abscess.
Dietary indiscretion Consumption of a hard object such as a bone fragment or hair which irritates the lining of the colon.
Food allergy Cats of any age can develop a food allergy to a particular ingredient. In cats, allergies typically affect the skin, although it can also affect the GI tract.
Inflammatory bowel disease Inflammation of the gastrointestinal tract. The cause still isn’t entirely understood but it is thought to be due to the presence of bacteria, dietary intolerance or parasites. Inflammatory cells infiltrate the mucosa leading to inflammation.
Blood clotting disorders Thrombocytopenia (low blood platelets) or hemophilia, which can cause internal bleeding.
Colitis Inflammation of the colon caused by infection, dietary intolerance, cancer, pancreatitis, bacterial infection, protozoa infection, stress. Colitis is a form of inflammatory bowel disease.
Poisoning Certain poisons such as rodenticide can cause blood clotting dysfunction leading to excessive internal bleeding.
Cancer Malignant growths, which can affect any part of the gastrointestinal tract or anal gland, cancers can occur in cats of any age, however, it affects older cats much more often.
Rectal, anal and colon polyps Benign (noncancerous) growths.

Other symptoms to watch for:

Watch for other symptoms as this information can assist your veterinarian in determining the cause.  Accompanying symptoms may include the following:

Often there will be no accompanying symptoms, but this doesn’t rule out an underlying problem. If you notice blood in your cat’s stool more than once or twice, it needs to be investigated, even without other symptoms present.

Diagnosing the cause:

If possible, bring along a stool sample or take a photo to show your veterinarian. If you suspect your cat has ingested poison, bring along the packaging if possible.

Your veterinarian will perform a complete medical and rectal examination and obtain a medical history from you. He will ask about your cat’s stool.

  • Is it firm and well formed with blood on the surface? This type of stool may be due to polyps, constipation or anal gland disorders.
  • Is it loose with blood mixed on the surface or mixed into the stool? This may be suggestive of an inflammatory or irritative disorder although cats with colitis can also pass firmly formed stools also.
  • Has your cat had any recent medications? Prescribed or nonprescribed.
  • When did you last worm your cat?

Cats who pass firm stools most often have constipation, polyps or anal gland issues. Whereas soft/loose stools are more commonly associated with inflammation or infections.

He will need to perform further tests to determine the cause of bleeding. These may include:

  • Complete blood count to look for infection, inflammation, anemia
  • Biochemical profile to determine the overall health of your cat
  • Urinalysis
  • Rectal examination
  • Fecal examination to check for parasites
  • Abdominal x-rays to look for growths, foreign bodies and check the internal organs
  • Abdominal ultrasound to look for growths, foreign bodies and check the internal organs
  • Biopsy – If a mass is found, your veterinarian may wish to perform a biopsy to examine a sample of the cells
  • Colonoscopy – Visual examination of the colon with an endoscope while the cat is under sedation. If necessary, tissue will be collected for biopsy
  • Coagulation profiles – To evaluate your cat’s blood clotting ability

Treating blood in stool:

Treatment depends on the underlying cause if one can’t be found your veterinarian may recommend putting your cat on a bland diet for a few days.

  • Constipation: Laxatives and/or stool softeners may be prescribed to treat constipation, increasing fibre and water consumption can also help.
  • Intestinal parasites (worms and cryptosporidium): De-worming medication to treat parasitic worms. There are no effective medications to treat cryptosporidium, however some veterinarians may prescribe antiprotozoal drugs, this is usually only given to immunocompromised cats such as those with feline immunodeficiency virus or feline leukemia. Supportive care is the mainstay of treatment for cryptosporidium including fluids to treat dehydration and anti-diarrheal medications.
  • Bacterial infections are treated with oral antibiotics and supportive care where necessary, this may include fluids to treat dehydration. Your cat may be put on a bland diet for a few days to rest the gastrointestinal tract if vomiting and diarrhea have occurred.
  • Food allergy: If a food allergy is suspected, your cat will be put on a special elimination diet, in which it will be fed a prescription diet which it has had no prior exposure to (such as duck or kangaroo), no other foods or treats should be given at this time. If the allergy symptoms clear up, the cat will then be challenged by re-introducing him to his previous diet. If the allergies return, it is determined the food is the cause of the allergy and your cat will be switched to another brand or type of food.
  • Polyps and tumours: These will require surgery to remove them, tumours may also be treated with chemotherapy.
  • Foreign object: Your veterinarian may give your cat an enema to try and flush out foreign body. If this isn’t possible, surgery will be required to remove the object(s).
  • Impacted anal glands: If the anal glands are impacted, your veterinarian will drain the glands and flush out with antibiotics. If the problem recurs then your veterinarian may decide to remove the anal glands.
  • Inflammatory bowel disease: A highly digestible, high-fibre, low fat diet may be prescribed. These diets are made up of a single source of protein, usually chicken or soy. Medications to suppress the over-active immune system such as corticosteroids, Azathioprine and Sulfasalazine may be prescribed. Antibiotics such as metronidazole may also be necessary.
  • Blood clotting disorders: Finding and treating the underlying cause if possible. Supportive care such as whole blood or plasma transfusions may also be necessary as well as Vitamin K injections.
  • Poisoning: Evacuating the poison from the cat if possible, this may be by inducing vomiting or pumping the stomach. Vitamin K injections may be given to help with blood clotting.
  • Colitis: See inflammatory bowel disease.
  • Panleukopenia: The prognosis is guarded, kittens are at greatest risk due to their immature immune system. Supportive care is necessary while the cat fights the infection. This may include blood transfusions, antibiotics to fight secondary bacterial infections (they won’t kill the panleukopenia virus), fluid and electrolyte replacement and nutritional support.


  • Slippery elm is a herbal remedy which has many medical uses. It contains a mucilige (a gelatinous substance) which coats and soothes the intestines and stomach as well as increasing mucus secretion which protects the gastrointestinal tract.
  • Probiotics: While giving dairy to a cat is generally not recommended, especially a cat with diarrhea, yoghurt is the exception. Yoghurt contains a type of bacteria known as Lactobacillus. These bacteria normally reside in the intestines, helping with the digestion of food. Sometimes the natural flora of the gut is thrown out of balance (for example if your cat is on a course of antibiotics), and this can lead to opportunistic and pathogenic strains of bacteria to take hold.