Why is my cat pooping outside the litter box?

4 min read Updated on October 8, 2026

In shortA cat who poops outside the litter box almost always has a specific reason: something makes going uncomfortable (constipation, diarrhea, pain when squatting, arthritis) or the box itself is the problem (dirty, too small, covered, new litter, bad spot). Some cats also want one box for urine and another for stool. It is never revenge. A 2020 review points out that pain often hides behind house soiling and should be ruled out first, so the vet comes before anything else.

What it often means

A box that no longer suits him: not clean enough, too small, covered, scented or new litter. He then often goes right next to it.
A digestive problem: diarrhea is urgent and he does not make it in time; constipation hurts, and he links the box to the pain.
Pain getting in or squatting: arthritis, especially in older cats, stiff hips, with a rim too high to step over. He goes on the edge or just in front.
One box for two jobs: some cats want one box for urine and another for stool, especially once the first one is already soiled.
Stress or conflict: a move, a new pet, another cat blocking the way. Stool left in plain sight may then sometimes serve as a marker.

Signals to read at the same time

The exact spot: right against the box, he was half in or hanging over the edge; scattered along the way, it fell out en route; far away and always in the same place, he is avoiding the box.
The stool: small, hard and dry suggests constipation; soft, liquid, with mucus or blood, the gut; normal, look at the box and the mood at home instead.
His visits to the box: does he still pee there, dig, sniff and leave, strain for a long time, cry? Film him discreetly.
His mobility: does he hesitate to step over the rim, jump on the couch less, walk with stiff hind legs? In older cats, it is often arthritis.
What changed: new litter, box moved, a cleaning product, a new pet, a new schedule. And with several cats: who hangs around near the box?

What you can do

Start with the vet, bringing a fresh stool sample in a bag and a short video of him at the box: both help find the cause.
Add a second box where he goes, or right next to the first: large, open, low rim, fine unscented litter. Keep the old one too.
Scoop stool at least once a day, and clean the soiled spot with an enzymatic cleaner, never bleach or ammonia.
For a senior, pick a low-entry box or cut a doorway into the side; for a long-haired cat, ask a groomer or your vet for a sanitary trim around the anus.
Do not scold him or rub his nose in it: he would link the box, or you, with fear, and start going where you cannot see him.

When to see a vet

See your vet if the stool is hard and dry, runny, mucusy or bloody, if he strains or cries in the box, licks his rear end, vomits, loses weight or has not gone in more than two days. Constipation, colitis, parasites, anal gland trouble and arthritis are classic causes, plus cognitive decline in older cats. Warning: a cat straining with nothing coming out may have a urinary blockage, not constipation. In males especially, that is an emergency.

Frequently asked questions

He pees in the box but poops next to it. Why?

Often because he prefers to keep urine and stool apart, or because a box he has already wet no longer suits him. Sometimes constipation hurt him there. Once his health is checked, a second box right next to the first often solves it. If he also pees elsewhere, our guide to peeing outside the litter box covers the urinary causes.

My senior cat poops next to the box. Is it just age?

Age is not a cause in itself. In older cats you mostly find arthritis that makes stepping in painful, constipation that becomes more common, and sometimes cognitive decline. A low-rim box, one box per floor and a vet checkup often change everything.

Is he doing it to get back at me?

No. Revenge does not exist in cats. He is avoiding a box that bothers him, a pain, or a spot where he does not feel safe. Punishing him adds fear and often pushes him to go in hidden spots, behind furniture.

It started when we got a second cat. What should I do?

Watch whether one cat blocks the box, sits in front of it or ambushes the other on the way out. The 2013 feline environmental needs guidelines list multiple, separated resources among the five pillars for indoor cats. In practice: one box per cat plus one, in different rooms, with two exits if possible.

Sources

The studies this page relies on, with a link to the original publication.

Ellis et al. (2013). AAFP and ISFM feline environmental needs guidelines. Journal of Feline Medicine and Surgery.Five pillars for an indoor cat: a safe place, multiple separated resources, chances to play and hunt, predictable human interaction, and surroundings that respect his sense of smell.
Mills et al. (2020). Pain and problem behavior in cats and dogs. Animals.Review: pain often hides behind a problem behavior (aggression, house soiling, licking), and should be ruled out first.

Mimo reads behavior. It does not replace a vet.