Is blood from my cat's bottom always an emergency?

No, but it always warrants a vet's involvement. A little blood streaking otherwise-normal stool in an otherwise-normal cat can usually wait for a same-day or next-day appointment. Heavy bleeding, a suspected toxin like rat bait, pale gums, weakness, or a string hanging from the rear are true emergencies.

My cat has a string hanging from their bottom. What do I do?

Go to a vet immediately and never pull on it. A linear foreign body saws through the intestines as it moves, and pulling a string can cut through the intestinal wall. This is a surgical emergency.

How can I tell where the blood is coming from?

If your cat tolerates it, gently lift the tail and look. Note whether the blood is a surface streak on the stool, mixed all through it, or coming from a cut or swelling around the anus, then describe exactly what you see to your vet.

Illness & Conditions

Blood From Your Cat's Rear: Wait-and-See, or Drive Now?

The first question when you spot blood is not what caused it, but how fast you need to move. An emergency vet sorts the red flags from the wait-till-morning cases, then the causes behind each.

By Dr. Lena Park, Emergency & Critical Care

February 3, 2026 · 6 min read

Link copied

You have found blood, in the litter box, on the bedding, or smeared where your cat just scooted, and your stomach has dropped. Before you spiral, know this: the useful first question is not “what is this?” It is “how fast do I need to move?” Most rectal bleeding in cats is not a life-threatening emergency, but some of it is, and the two look similar enough at 10 p.m. that the triage matters more than the diagnosis. So let us sort the fast lane from the slow lane first, then work through the causes behind each.

The drive-now list

Get your cat to a vet or an emergency clinic right away, tonight, if the bleeding comes with any of these:

Heavy or continuous bleeding rather than a streak
Pale or white gums, weakness, collapse, or lethargy
Known or even suspected poisoning, especially rodenticide (rat bait)
A string, thread, or other material hanging from the anus (do not pull it)
Recent trauma, an open wound, or obvious severe pain
Vomiting, bruising anywhere on the body, or a distended belly

“Rat bait is the one I never want anyone to wait on,” says Dr. Lena Park, an emergency veterinarian who contributes to Pet Times. “Rodenticides stop the blood from clotting, so bleeding from anywhere, including the rear, can be the first sign, and by the time it shows up the clock is already running. If there’s any chance your cat got into it, that’s an emergency, and bring the packaging so we know which type.”

The wait-a-bit list

If your cat is bright, eating, and acting completely normal, and you are seeing a little blood streaking on otherwise-formed or slightly-loose stool, it is usually reasonable to book a same-day or next-morning appointment rather than rushing the ER. When you genuinely cannot tell which lane you are in, call a clinic and describe what you see; a phone triage costs nothing and beats guessing.

Do a two-minute investigation before you go

The single most helpful thing you can do is figure out roughly where the blood is coming from, because it changes what your vet looks for first. If your cat will allow it, gently lift the tail and look. Then note three things to relay at the appointment: Is the blood a surface streak on the stool, or mixed all the way through it? A surface streak points toward the rectum or anus; blood blended through the stool points higher up the digestive tract. Are there cuts, puncture wounds, lumps, redness, or swelling around the anus or the anal gland area (roughly the four and eight o’clock positions)? And is there any foreign material poking out? If so, leave it completely alone and head in.

A quick anatomy note so the terms make sense: the rectum is the last stretch of the large intestine where stool collects, the anus is the opening it passes through, the anal glands are two small scent sacs beside the rectum, and the perineum is the skin between the anus and the genitals. Bleeding can start in any of them.

The causes, sorted by how worried to be

Usually manageable, still worth a visit. Anal sac disease is common: the fishy-smelling fluid in the anal glands normally empties during a bowel movement, but when it does not, the sacs can become impacted, infected, or abscessed, and treatment is expressing them, plus antibiotics if there is infection. Constipation is another frequent culprit; a cat straining over hard, oversized stool can tear the rectum on the way out, and the fix is treating the underlying cause, from dehydration to arthritis pain. Intestinal parasites can inflame the gut enough to bleed, and a simple fecal test tells your vet which dewormer to use.

Needs a real workup. Polyps are usually benign growths that can bleed when stool brushes them, but other intestinal growths can be malignant, so they get investigated rather than assumed. Inflammatory bowel disease produces chronic inflammation and intermittent blood in the stool, and is managed with diet and medication. Here is a distinction the older advice often glossed over and that newer veterinary thinking emphasizes: in cats, IBD and a low-grade intestinal lymphoma can look nearly identical early on, with the same waxing-and-waning digestive signs. That overlap is exactly why persistent or recurring bleeding deserves a thorough diagnostic workup, not repeated rounds of symptomatic treatment that could let a treatable cancer coast for months.

True emergencies. A linear foreign body, that swallowed ribbon or length of yarn, is the one that kills the “wait and see” instinct entirely. As it travels, string saws against the intestinal wall and causes catastrophic damage; it requires surgery, and pulling on a visible end can make it worse. Rectal prolapse, where the rectum protrudes through the anus after hard straining (more common in kittens with heavy worm burdens), is also a get-seen-now problem.

What treatment looks like, and one thing to know about parasites

Because treatment depends entirely on the cause, your vet’s job is first to find it, and some steps, like an enema, lancing an abscessed gland, or reducing a prolapse, have to happen in the clinic. Once your cat is stable, at-home follow-up may include a bland diet, a diet trial to rule out food allergy, probiotics, dewormers, antibiotics, fiber, easier access to fresh water, and more frequent litter box cleaning.

One point worth flagging for the whole household: several of the intestinal parasites that cause bleeding in cats, including roundworms and hookworms, are zoonotic, meaning they can infect people, particularly children. That is a strong practical argument for the broad, year-round parasite prevention your vet recommends and for prompt fecal testing rather than waiting to see if the blood clears on its own.

Can you prevent it?

You cannot guarantee your cat will never have rectal bleeding, but you can lower the odds of the conditions that cause it: stay consistent with monthly parasite preventatives, keep up with routine exams so problems are caught early, feed a well-balanced diet, make sure fresh water is always available to head off constipation, help your cat hold a healthy weight, and keep string-like objects, shoelaces, yarn, tinsel, out of reach entirely.

The bottom line

Blood from your cat’s rear is common enough to have ordinary causes and serious enough that it should never be ignored. Triage first: if any drive-now sign is present, go. If not, investigate, note what you see, and get your cat in front of a vet promptly rather than diagnosing from the couch. The cause is theirs to find; the fast, calm response is yours.