Blood in Your Cat's Stool: Causes, When to Worry, and What To Do

Discovering blood in your cat's litter box is understandably alarming. Whether it appears as bright red streaks alongside formed stool or dark, tarry-looking feces, blood in a cat's bowel movements signals that something is happening inside their digestive system — and the type of blood, the amount, and your cat's overall behavior together determine whether this warrants immediate emergency care or careful monitoring at home.

Understanding the Two Types of Blood in Cat Stool

Hematochezia (Bright Red Blood)

Bright red, fresh-looking blood in or around your cat's stool indicates bleeding in the lower digestive tract — the colon, rectum, or anus. Because the blood hasn't traveled far through the digestive system, it hasn't been digested and appears red. This type is generally considered less urgent than dark blood, though it still warrants attention.

Common causes of hematochezia in cats include:

• Colitis — inflammation of the large intestine, frequently triggered by stress (a new pet, visitor, move, or schedule change), a sudden diet switch, or an intestinal infection
• Constipation — straining repeatedly to defecate can rupture small blood vessels in the rectal lining
• Intestinal parasites — hookworms, Giardia, and Tritrichomonas foetus (a protozoal parasite common in young cats from multi-cat environments) all cause bloody stool with mucus
• Rectal polyps — benign growths in the lower bowel
• Anal gland disease — impacted or infected anal glands cause irritation and bleeding around the anus

Melena (Dark, Tarry Stool)

Melena appears as dark, black, tar-like, or coffee-ground-textured stool. It indicates bleeding higher in the digestive tract — the stomach or small intestine. The blood has been fully or partially digested during its journey through the GI tract, which is why it appears dark rather than red. Melena is generally a more serious finding than hematochezia and warrants prompt — often same-day — veterinary evaluation (AAFP-AAHA Feline Life Stage Guidelines, 2021).

Causes of melena in cats include stomach or small intestinal ulcers, foreign body ingestion, intestinal lymphoma or other tumors, and systemic clotting disorders.

Stress Colitis

Cats are highly sensitive to environmental change, and acute stress colitis is one of the most common causes of bloody stool in otherwise healthy cats. A new family member, a new pet, a recent boarding stay, construction noise, or even a change in the daily routine can trigger inflammation of the colon. The stool is typically soft, more frequent than usual, and contains small amounts of bright red blood and mucus. Affected cats are usually still eating, grooming, and behaving normally otherwise.

When To Seek Emergency or Same-Day Veterinary Care

Contact your vet promptly or go to an emergency clinic if:

• The amount of blood is large rather than small streaks
• The stool appears dark, black, or tarry (melena)
• Blood is accompanied by vomiting, lethargy, appetite loss, or weight loss
• Your cat is straining repeatedly in the litter box and producing little or nothing — note carefully whether the straining is to defecate or to urinate. Male cats that cannot urinate have a life-threatening urethral blockage requiring emergency care within hours.
• Pale or white gums — suggests significant blood loss
• Known or suspected ingestion of a toxin, foreign object, or medication
• Symptoms persist for more than 24 hours or are clearly worsening
• Your cat has lost weight alongside recurring bloody stools

What To Do at Home

If your cat is passing a small amount of bright red blood alongside an otherwise normal stool, is acting completely normal, and has none of the emergency signs above, you may monitor at home for 12 to 24 hours:

1. Observe closely — is the blood increasing? Is your cat eating, drinking, and using the litter box normally?
2. Offer a bland diet temporarily — plain boiled chicken (no seasoning) can reduce GI inflammation while the gut settles.
3. Assess for recent stressors — did anything change in the home recently? New pet, visitor, move, or boarding?
4. Keep fresh water available at all times — hydration supports gut recovery.
5. Never give human medications — ibuprofen, acetaminophen, and aspirin are highly toxic to cats and can themselves cause GI bleeding.
6. Save a stool sample in a sealed bag if you can — your vet may want it for parasite testing.

Any case involving dark stool, large amounts of blood, or a cat that is unwell in any way requires same-day veterinary attention.

Frequently Asked Questions

What does blood in my cat's stool mean? The type matters. Bright red blood (hematochezia) means bleeding in the lower tract — the colon, rectum, or anus — often from colitis, constipation, parasites, polyps, or anal gland disease, and is generally less urgent. Dark, black, tarry stool (melena) means bleeding higher up (stomach or small intestine) and is more serious, warranting prompt, often same-day, veterinary evaluation.

Is blood in cat stool an emergency? Seek prompt or emergency care if the amount is large (not small streaks), the stool is dark/black/tarry, blood comes with vomiting/lethargy/appetite loss/weight loss, your cat strains and produces little (a male cat straining to urinate can have a life-threatening blockage — get help within hours), gums are pale or white, you suspect a toxin or foreign object, or it lasts more than 24 hours.

Can stress cause bloody stool in cats? Yes — acute stress colitis is one of the most common causes in otherwise-healthy cats. A new family member or pet, boarding, construction noise, or a routine change can inflame the colon. The stool is typically soft and more frequent with small amounts of bright red blood and mucus, while the cat keeps eating, grooming, and behaving normally.

What can I do at home for a cat with a little blood in the stool? If it's a small amount of bright red blood with an otherwise normal stool and no emergency signs, you can monitor for 12-24 hours: observe closely, offer a bland diet (plain boiled chicken), check for recent stressors, keep fresh water available, and never give human medications (ibuprofen, acetaminophen, and aspirin are toxic to cats). Save a stool sample if you can. Any dark stool, large amount of blood, or an unwell cat needs same-day care.

Still Not Sure if Your Cat Needs a Vet?

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