Blood in your cat’s stool usually signals irritation or inflammation somewhere in the digestive tract. It can range from a minor, self-resolving issue like a dietary upset to something more serious like a parasitic infection or chronic bowel disease. The color and appearance of the blood tell you a lot about where the problem is and how urgently your cat needs help.
What the Blood Looks Like Matters
Bright red blood in or on the stool means the bleeding is coming from the lower digestive tract, typically the colon or rectum. You might see red streaks on the surface of the poop, or the entire stool may look bloody. This is the more common presentation in cats and often points to colitis (inflammation of the large intestine), straining, or irritation near the end of the digestive system.
Black, tarry stool is a different situation. That dark color means the blood has been digested, which places the source much higher up, in the stomach or small intestine. Tarry stool can indicate more serious internal bleeding and is harder to spot because it doesn’t look obviously “bloody.” If your cat’s stool suddenly looks unusually dark and sticky, treat that as a red flag.
Common Causes in Adult Cats
Colitis is one of the most frequent reasons for bloody stool. The colon becomes inflamed, producing diarrhea that often contains fresh blood and mucus. Colitis itself isn’t a single disease; it’s a response that can be triggered by infections, stress, dietary problems, or chronic conditions like inflammatory bowel disease.
Food intolerance or a sudden diet change can irritate the gut enough to cause bleeding. If your cat ate something unusual, got into food they shouldn’t have, or you recently switched their diet without a gradual transition, that’s a likely culprit. Some cats are genuinely allergic to specific proteins like chicken or beef, and repeated exposure keeps the gut inflamed.
Stress is an underappreciated cause. A new pet in the home, a move, a change in routine, or even a trip to the vet can upset a cat’s digestive system enough to produce bloody stool. This is especially true for cats that are already prone to a sensitive stomach.
Parasites and Infections
Intestinal parasites are a major cause of bloody stool, particularly in kittens and outdoor cats. The Cornell Feline Health Center notes that common symptoms of gastrointestinal parasites include bloody or mucousy feces, diarrhea, vomiting, weight loss, and a dull coat.
Hookworms attach to the intestinal wall and feed on blood. In severe cases, the blood loss is significant enough to cause anemia, and the stool turns black and tarry from digested blood. Coccidia, a single-celled parasite, spreads through contaminated feces and is extremely common. Nearly all cats encounter it at some point in their lives, usually by ingesting microscopic cysts from the environment or from infected insects like flies and cockroaches. Giardia spreads the same way, typically passed between cats sharing a litter box.
Bacterial infections from organisms like Salmonella, E. coli, and Clostridia can also cause bloody diarrhea. Viral infections are a concern too, especially feline panleukopenia (sometimes called feline distemper), which carries a mortality rate of roughly 90% in unvaccinated kittens. Vaccination is the primary defense against this virus.
Kittens Face Different Risks
Almost every kitten is born carrying some intestinal worm burden, so parasites are the first thing to rule out in a young cat with bloody stool. Coccidia and Giardia are also seen frequently in kittens, partly because their immune systems are still developing and partly because they’re often in close contact with other young cats.
Dietary issues hit kittens hard. Abrupt food changes are one of the most common triggers for bloody stool in young cats. Many kittens are also lactose intolerant, so dairy products (a common well-meaning offering) can cause significant GI upset. Some are intolerant to specific proteins like chicken, beef, wheat, or potatoes.
Kittens are also more vulnerable to stress-related colitis. Rehoming, changes in routine, and new environments frequently trigger inflammation in the colon that produces bloody, slimy diarrhea. A rare but serious condition called intussusception, where a section of intestine telescopes inside itself, can also occur in young cats and requires immediate veterinary attention.
Inflammatory Bowel Disease
If your cat has recurring episodes of bloody stool along with vomiting, weight loss, lethargy, or poor appetite, inflammatory bowel disease (IBD) may be the underlying issue. IBD involves chronic inflammation of the GI tract, and when the colon is affected, diarrhea with or without blood is a hallmark symptom.
Managing IBD typically starts with dietary changes. Your vet may recommend a hypoallergenic diet to rule out food triggers. If that doesn’t help, high-fiber, low-fat, easily digestible foods are the next step. Some cats respond well to probiotics or added soluble fiber like psyllium. Cats with IBD may also become deficient in B vitamins, particularly folate and B12, which need to be supplemented.
When diet alone isn’t enough, medication enters the picture. Treatment often requires trying different combinations before finding what works for a particular cat. The good news is that IBD can usually be controlled well enough for your cat to live comfortably. The challenge is that it requires ongoing management, and flare-ups can happen. Strict consistency with diet and regular monitoring are essential for keeping symptoms in check.
Swallowed Objects
Cats are notorious for swallowing things they shouldn’t, especially string, ribbon, thread, and rubber bands. These “linear foreign bodies” are particularly dangerous because as the intestine tries to move them along, they can bunch up the intestinal wall. The repeated sawing motion of the material against the tissue can tear through the intestinal lining, causing internal bleeding and potentially life-threatening infection. Don’t assume the object will simply pass on its own, because with linear foreign bodies, that often doesn’t happen.
What Your Vet Will Do
A veterinary workup for bloody stool typically starts with a physical exam that includes a rectal examination to check for abnormalities in the mucosal lining. Multiple fecal samples (not just one) are analyzed to look for parasite eggs, cysts, and bacterial overgrowth, since parasites don’t shed consistently and a single sample can miss them.
If the problem persists or the initial tests don’t reveal a cause, your vet will likely recommend bloodwork, including a complete blood count and chemistry panel. For cats, testing for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) is also standard, since both can affect the immune system and make GI problems worse. Older cats may have their thyroid levels checked as well.
Imaging comes next if needed. Abdominal X-rays can sometimes reveal foreign objects or narrowing in the intestine. Ultrasound gives a more detailed look at the intestinal wall layers and can identify thickening or masses. In cases where the cause remains unclear, a colonoscopy allows direct visualization of the colon’s surface and lets the vet take tissue biopsies from multiple locations for microscopic examination.
Signs That Need Emergency Care
A small amount of bright red blood on an otherwise normal stool, happening once, is worth monitoring but isn’t 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 (a sign of blood loss or poor circulation)
- Repeated vomiting alongside the bloody stool
- Severe or worsening diarrhea
- Signs of pain such as hunching, crying, or hiding
- Weakness or lethargy
- Very young kittens, senior cats, pregnant cats, or cats with existing health conditions
These signs suggest significant blood loss, dehydration, or a rapidly progressing condition that needs professional intervention before it becomes life-threatening.
What You Can Do at Home
If the bloody stool is a one-time event with no other symptoms, you can try a brief period of bland feeding. The traditional approach is boiled chicken breast mixed with plain cooked white rice. This is gentle on the stomach and gives the gut a chance to calm down. Keep in mind that this combination is not nutritionally complete for cats, so it’s only a short-term measure, not a long-term diet.
During this time, keep a food diary. Weigh what you offer (a kitchen scale helps), note what your cat actually eats, and track stool consistency and any blood you see. This information is genuinely useful if you end up at the vet, because it helps narrow down dietary triggers and gives a clear picture of how quickly things are improving or getting worse. If the bloody stool continues beyond a day or two, or if any additional symptoms appear, it’s time for a professional evaluation.