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Blood in Cat Poop: What It Means and When to Worry

Cats / October 2, 2026 / 11 min read / PoopScout Team

You scooped the box, and there it was: a red streak on the poop, or a bloody puddle that was not there yesterday. Your cat may be curled up on the sofa as if nothing happened. Take a breath. What you saw tells you a lot.

Blood in the cat poop: red, black, or in between

The color of the blood is the first clue, because it tells you roughly where the bleeding is. Fresh red blood has not been digested, so it comes from low down: the colon, the rectum, or the skin around the bottom. Black, sticky blood has been through the stomach and small intestine; vets call it melena.

Mucus, a shiny jelly-like coating, often comes with the blood, and together they point to the large intestine. Cats with large-bowel trouble also go more often, pass small amounts, and strain at the end.

Not sure what color you are looking at? The cat poop color chart walks through each shade. The wider picture lives on our blood in poop hub, and the dog version is in why is my dog pooping blood.

Why is my cat pooping blood but acting normal?

This is the most common version of the story, and the most confusing one. Your cat is eating, grooming and chasing the laser dot, and yet there is blood on the poop.

Most fresh blood in cat poop comes from an irritated lining in the colon or rectum, not from anything that makes a cat feel sick. Inflammation, straining, or a hard stool scraping past can break a few tiny blood vessels there, and a little bright red blood ends up on the outside of the poop. Vets call this colitis when it goes on for a while, and they note that the physical exam is often unremarkable. The cat looks fine because, apart from the colon, the cat is fine.

So why call the vet at all? Because the things that irritate a cat's colon are often invisible, and two of the most common are parasites:

• Tritrichomonas, a microscopic parasite behind soft, smelly stool with blood or mucus, mostly in young cats and cats from shelters or catteries. A routine fecal test usually misses it, so your vet has to look for it on purpose.
• Giardia and coccidia, also microscopic, both shed by cats who look perfectly healthy. Coccidia is most common in kittens.

Add a sudden food change, a stressful week, or a bout of constipation, and you have most of the reasons a healthy-looking cat leaves a red streak in the box. None are emergencies, and all are easier to sort out early. That is why the verdict is Call your vet today, not Keep an eye.

Cat pooping blood: the common causes

Here is what vets find most often. Most of it sits under one umbrella, colitis, which just means an inflamed large intestine.

Parasites. Tritrichomonas, Giardia, coccidia and roundworms all irritate the gut. Hookworms are the exception that bleeds higher up: they feed on blood in the small intestine, and the stool can turn dark and tarry, especially in kittens. Our guide to worms in cat poop covers what you can and cannot see.

A diet change or a diet slip. Switching food overnight, a new treat, or something stolen off a plate can upset the colon for a few days. What to feed a cat with diarrhea explains why to ask your vet before changing anything.

Stress. A move, a new baby or a cat next door can all show up in the box as soft stool, mucus and a little blood.

Constipation and straining. A hard, dry stool can scrape the rectum on the way out and leave a streak of fresh blood. If your cat is passing small hard pieces or going in and out of the box, read cat straining to poop and the warning below.

Anal sac problems. Two small scent glands sit beside the anus. When one is blocked or infected you may see scooting, licking under the tail, and blood or sticky discharge near the bottom rather than on the poop.

Infections and inflammatory bowel disease. Bacterial and viral infections inflame the gut; in kittens and unvaccinated cats, panleukopenia (feline distemper) causes vomiting and often bloody diarrhea and is life-threatening. Inflammatory bowel disease is a long-running immune reaction in the gut lining that vets see as chronic vomiting, diarrhea and weight loss.

Something swallowed, or a poison. String, ribbon, hair ties and small toys can cut or block the gut; vomiting, belly pain and not eating after chewing something are reasons to call now. Many rat and mouse baits stop blood from clotting, and the first sign can be bloody or black stool days later. If there is any chance your cat ate rat or mouse bait or another poison, call your vet or ASPCA Animal Poison Control at (888) 426-4435 (a fee may apply), even if they seem fine.

Cat has bloody diarrhea: what changes

Blood on a formed stool and blood in diarrhea are different situations. Diarrhea means the gut is losing water as well as blood, and cats, especially small ones, run dry quickly. Here is how to read it on the 1 to 7 stool scale the app and many vets use: 2 is ideal (firm, segmented, easy to scoop), soft piles are a 5, no shape is a 6, and watery puddles are a 7.

Two rules hold whatever the score. Diarrhea that is mostly blood, or that looks like raspberry jam, is Call a vet now. So is blood plus vomiting, weakness, no appetite or pale gums, because that combination is how serious infections and poisonings present.

For cat diarrhea without blood, the waiting rules are a little more relaxed: see cat diarrhea: when to wait and when to call. The stool score checker helps you put a number on what you are seeing.

Blood in kitten poop

Kittens get a stricter rulebook. They have tiny reserves, so a night of bloody diarrhea can leave one dehydrated by morning. They are the age group most at risk from panleukopenia, a virus that causes vomiting and bloody diarrhea and can be deadly, especially before the vaccine series finishes around 16 to 20 weeks. And they pick up roundworms from their mother's milk and coccidia from their surroundings.

So the verdicts shift one step up:

• Any blood in a kitten's poop, even a bright and playful kitten: Call your vet today.
• Blood with vomiting, low energy, no appetite or pale gums, or black tarry poop: Call a vet now. Hookworms can cause dangerous blood loss in the very young.

Our guide to kitten diarrhea goes deeper on what is normal for a young cat.

Black cat poop: the one not to wait on

Black, sticky, tar-like poop usually means blood that was digested on its way through, so the bleeding is in the stomach or small intestine. The usual causes in cats are stomach ulcers, hookworms, something sharp that was swallowed, and rat or mouse bait, and some cause serious blood loss before a cat looks unwell. It is Call a vet or emergency clinic now, every time. Healthy gums are light pink; pale, white or gray gums mean your cat may already have lost a lot of blood. Black cat poop has the full picture, but do not read it instead of making the call.

What to do today

1. Take a photo before you scoop. Good light, straight above, then close on the blood. Note the time.
2. Check the gums. Light pink is normal. Pale, white or gray is Call a vet now.
3. Look at the whole cat. Eating? Vomiting? Hiding? Straining in the box? Write it down.
4. Bag a fresh sample. About an inch, in a clean sealed container, kept cool. Up to 24 hours in the fridge, away from food.
5. Keep fresh water out and do not change the food suddenly.
6. Do not give any human medicine. Several common human stomach and pain medicines are dangerous for cats. Ask your vet first, even about over-the-counter products and home remedies.
7. Think back. New food, a stressful change, anything chewed, any chance of poison. Then make the call that fits the lists below.

When to call the vet

Call a vet now

• Black, sticky, tar-like poop.
• A lot of fresh blood, or diarrhea that is mostly blood.
• Raspberry-jam diarrhea: bloody and jelly-like, often with vomiting.
• A kitten with diarrhea plus vomiting, low energy, or no interest in food.
• Pale or white gums, collapse, or severe weakness.
• Any chance your cat ate rat or mouse bait or another poison, even if they seem fine. Signs can take days to show. Call your vet or ASPCA Animal Poison Control at (888) 426-4435 (a fee may apply).
• A cat, especially a male, straining in the litter box with little or nothing coming out.
• String, thread, yarn, or tinsel hanging from the mouth or bottom. Do not pull it.
• Repeated vomiting with belly pain.

Call your vet today

• A small streak of fresh blood, or mucus with straining, in a cat who is otherwise well.
• Any blood in a kitten's poop, even a bright and playful one.
• Diarrhea lasting more than 24 to 48 hours, or diarrhea with a poor appetite or a vomit or two, in an adult cat who is still alert.
• Worms, or rice-like or sesame-like bits, in the poop or on the fur around the bottom.
• No poop for 2 to 3 days, repeated straining that only produces small hard pieces, or blood that keeps coming back.

A streak of blood in the litter box is frightening, and it is also one of the most common reasons cat owners ring their vet. Most of the time the cause is an irritated colon with a fixable reason behind it, and a fecal test is the usual first step. Photograph it, bag it, check the gums, and make the call that fits. The PoopScout app reads a photo for score, color and findings and gives you one of these four verdicts, so you have a clear next step before you pick up the phone.

PoopScout guides are general information for pet owners, written from veterinary sources named above. They are not veterinary advice, they do not diagnose, and they can be wrong for your pet. If your dog or cat seems unwell, or you are worried, call your vet. In an emergency, contact your vet or the nearest emergency animal hospital right away.