Bleeding from your cat’s rear end usually points to a problem in the lower digestive tract, anal glands, or the rectal area itself. The causes range from minor issues like constipation to more serious conditions like infections or tumors. The color and amount of blood, along with your cat’s behavior, can help you figure out how urgent the situation is.
What the Blood Looks Like Matters
Bright red blood on, around, or mixed into your cat’s stool points to a problem in the colon, rectum, or anus. This is the most common type you’ll notice, and it means the blood hasn’t been digested, so the source is close to the exit. You might see it streaked on the stool, dripping after your cat uses the litter box, or smeared around the area itself.
Black, tarry stool is a different signal entirely. That dark color means the blood has been partially digested, which places the source higher up in the digestive tract, like the stomach or small intestine. It’s harder to spot but just as important. If you see either type, pay attention to how much blood there is and whether it’s happening once or repeatedly.
Anal Gland Problems
Cats have two small sacs just inside the anus that produce a strong-smelling fluid normally expressed during bowel movements. When these sacs don’t empty properly, they become impacted. The contents thicken, the gland swells, and your cat gets increasingly uncomfortable. You might notice your cat scooting across the floor, licking or biting at the area obsessively, or leaving traces of foul-smelling discharge on surfaces.
If impaction goes untreated, the gland can become infected and eventually form an abscess. A ruptured anal gland abscess releases pus and blood, which is often what owners notice first. The area near the anus may look swollen, red, or have an open wound. This is painful for your cat and needs veterinary treatment to clean the wound and address the infection.
Constipation and Straining
Hard, dry stool can scrape and tear the delicate tissue lining the rectum and anus as it passes. If your cat is visibly straining in the litter box, producing small hard pellets, or going less frequently than usual, constipation is a likely culprit. The bleeding in these cases is typically minor, with small amounts of bright red blood on the surface of the stool or left in the litter box afterward.
Dehydration, low-fiber diets, and reduced activity all contribute to constipation in cats. Some owners add canned pumpkin to their cat’s food as a fiber source, but the amounts typically given (a quarter teaspoon to two tablespoons) provide far less fiber than you might think. Researchers at Tufts University pointed out that matching the fiber content of a therapeutic high-fiber diet would require over two and a half cups of pumpkin per day for a cat. A veterinarian can recommend the right type and amount of fiber, or a specific diet, if constipation is recurring.
Colitis and Inflammatory Bowel Disease
Colitis, or inflammation of the large intestine, is one of the most common reasons cats pass blood in their stool. The inflamed lining of the colon produces mucus and bleeds easily, so you’ll often see stools that are loose, coated in a slimy film, and streaked with fresh blood. Your cat may also strain to go, visit the litter box more frequently, and pass only small amounts each time.
Inflammatory bowel disease (IBD) is a chronic form of this problem where the immune system causes ongoing irritation to the intestinal lining. IBD is one of the most important non-cancerous causes of gastrointestinal bleeding and ulceration in cats. It can affect any part of the digestive tract, but when it targets the large intestine, bloody mucous diarrhea is the hallmark symptom. Diagnosis usually requires a combination of blood work, stool testing, and sometimes endoscopy to take tissue samples from the intestinal wall.
Intestinal Parasites
Worms are a straightforward and treatable cause of rectal bleeding, especially in outdoor cats, kittens, or cats in multi-cat households. Hookworms are particularly damaging because they physically latch onto the intestinal lining and feed on blood. Over time, this causes chronic blood loss, bloody diarrhea, weight loss, and pale gums from anemia.
Other parasites can also irritate the intestinal lining enough to cause bleeding. Your vet can identify most common worms through a fecal flotation test, which examines a stool sample under a microscope for parasite eggs. Some parasites require additional testing methods, like a wet mount examination or specialized screening. Regular deworming, especially for cats that go outdoors, prevents most parasitic infections from reaching the point of visible bleeding.
Tumors and Growths
In older cats, bleeding from the rectal area can sometimes indicate a growth. Benign polyps in the rectum or colon can bleed when stool passes over them. Colorectal adenocarcinoma, the second most common gastrointestinal cancer in cats, tends to appear in older animals and is often discovered only after symptoms like bloody stool, constipation, vomiting, or weight loss become noticeable.
A single episode of minor bleeding in a young, otherwise healthy cat is unlikely to be cancer. But in a senior cat with persistent or worsening symptoms, especially combined with weight loss or changes in appetite, a thorough workup including imaging or endoscopy with biopsies may be needed to rule out or identify a tumor.
Signs That Need Emergency Care
A small streak of blood on an otherwise normal stool, happening once, is worth monitoring but not necessarily an emergency. However, certain combinations of symptoms mean your cat needs to be seen immediately:
- Large amounts of blood in or around the stool
- Pale, blue, or deep red gums (check by gently lifting the lip)
- Repeated vomiting alongside the bleeding
- Severe or worsening diarrhea
- Lethargy or weakness, especially if your cat won’t get up or seems unsteady
- Pain, shown by crying, hiding, or resisting being touched near the abdomen or rear
Very young kittens, senior cats, pregnant cats, and cats with existing health conditions are at higher risk of rapid deterioration from blood loss or the underlying cause. For these cats, even moderate bleeding warrants prompt veterinary attention.
What Happens at the Vet
Expect the visit to start with a physical exam, including a look at (and sometimes a digital exam of) the rectal area to check for masses, swelling, or anal gland issues. A fecal sample will likely be tested for parasites, and a thin smear of stool may be examined for signs of infection or inflammation. Blood work helps assess whether your cat has lost enough blood to become anemic and checks for underlying conditions like kidney disease that could be contributing.
If these initial tests don’t explain the bleeding, or if symptoms are chronic or severe, your vet may recommend endoscopy. This allows direct visualization of the colon, rectum, and portions of the small intestine, and lets the vet take small tissue samples to check for inflammatory bowel disease or cancer. Most cats recover quickly from the procedure itself, though sedation or anesthesia is required.