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What Causes Blood in Cats' Stool?

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

Many owners become concerned when they find blood in their cat's stool.

Many owners become concerned when they find blood in their cat's stool.

Upon noticing blood in their cat's stool, many pet owners become concerned that their cat may have cancer. However, it may be reassuring for cat owners to learn that blood in their pet's stool is usually caused by something less serious.

Common Causes of Blood in Cats' Stool

  • Injury: In order to locate possible injuries, the cat's rectal area, including the anal sac area, should be inspected carefully. Sometimes, the passage of dry stools may cause limited bleeding. In some cases, the ingestion of sharp bones may scrape on the lower intestine or rectal area as they pass. This causes a small amount of bleeding.
  • Parasites: Cats may be affected by various parasites and protozoans that may cause irritated bowels and blood in the stool. Roundworms, hookworms, coccidia are often the culprits. A fecal test will be able to detect them.
  • Rectal Polyps: These are benign masses that present in the rectal area. They tend to be highly vascularized. This causes them to bleed easily when the feces passes through the rectum.
  • Dietary Intolerance: Foods that cause allergies, sudden diet changes, intolerance, or other complications that may irritate the lower bowels, may eventually cause blood in the stools.
  • Rat Poison Ingestion: Rat poison is meant to cause rodents to bleed to death. If a cat indirectly eats a poisoned rat, or if the cat directly eats some rat poison, it will interfere with the cat's blood clotting system. This causes spontaneous bleeding from the rectum, mouth, nose, or under the skin.
  • Blood Clotting Disorders: In this case, the cat may be affected by a disorder that interferes with the proper clotting of the blood. In this case, the cat will bleed. Sometimes this is spontaneous, or it can occur with a minimum amount of trauma.
  • Cancer: While not very common, cancer is always a possibility and should be ruled out—especially when dealing with senior pets.
If you see blood in your cat's stool, don't freak out! It's most likely caused by an ulcer or a small bone. Both are easily treated.

If you see blood in your cat's stool, don't freak out! It's most likely caused by an ulcer or a small bone. Both are easily treated.

Where Does the Blood Come From in Stools?

First of all, it is important to learn about where the blood is deriving from. As a general rule, fresh red blood (medically known as hematochezia) usually derives from either the lower intestines, or the rectum.

It is very important to find out if the blood is actually coming from the rectum and not from the urethra. Cats, at times, may suffer from urinary tract infections where they may strain to urinate. These infections produce bloody drops of urine. In this case, if the cat is a male, the risks of a urinary blockage are high and life-threatening. If this is the case, then the cat may require immediate veterinary treatment.

On the other side of the spectrum, the presence of black, tarry, blood (medically known as melena) derives most likely from the upper intestinal tract and stomach. In this case, the dark color derives from digested blood. This is often seen in cats suffering from bleeding stomach ulcers.

As you can see, there are various causes of blood in a cat's stools. If the bleeding episode is a one-time ordeal with minimal bleeding and the cat is bright and alert, very likely it may be something minor that will not continue to persist. However, if the cat has a lot of blood loss, exhibits pale gums (suggesting anemia) and the bleeding episodes continue, a prompt vet visit is highly recommended.

If your cat has bloody stools, please consult with a veterinarian for a hands-on examination.

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This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2009 Adrienne Farricelli


Alex on November 26, 2017:

I think this site is really good helpful and even interesting

Adrienne Farricelli (author) on May 27, 2012:

Thanks a bunch! All the time I worked for my vet never encountered a case with Spirocerca Lupi, maybe it is more common in certain areas than others? quite interesting, looking this parasite up...

Joe Njenga from Nairobi Kenya on May 27, 2012:


I think parasitism and poisoning are the highest on the list of the causes of blood in the cat's stool. You should also ensure you look at the nature of the blood in the feces since it may be helpful for identifying the cause. Example: Blood in feces that seems to have gone through the entire GIT would be more likely come from the upper GIT. In dogs, the Upper GIT may at times be infected by a notorious worm Spirocerca Lupi. All the same your hub is comprehensive and well written, thanks

Kathy from Independence, Kansas on January 24, 2011:

Thank you, alexadry, for this really informative hub. You've answered several of my concerns, keeping in mind the caveat you've included at the conclusion of this article. I appreciate your indepth discussion about this condition; and all the possibilities listed are, indeed, useful to know...and, yes, of course, one should consult a Veterinarian when / if there is doubt. Great article! Thank you!

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