A cat that stops using the litter box is not being spiteful. Something about its body, its box or its household has changed, and the puddle on the bath mat is how it tells you. Most causes can be found with some careful watching, and many can be fixed.
Rule out medical problems first
Many cats who go outside the box are sick or in pain. Bladder inflammation or infection, bladder stones, kidney disease, diabetes, an overactive thyroid, constipation and arthritis can all lead to accidents. A cat with a painful bladder may link the box with that pain and go elsewhere.
Go to a vet immediately, or to an emergency clinic, if you see any of these:
- A male cat straining in the box and producing little or no urine. This can mean a blocked urethra, which is life-threatening and can become fatal quickly. Don’t wait until morning.
- Crying out while trying to pee, or going back to the box again and again
- Blood in the urine
- Vomiting, hiding, not eating or unusual weakness alongside litter changes
- Straining to pass stool with nothing coming out
Book a vet visit soon if:
- Your cat is drinking or peeing noticeably more than usual
- The stool is very hard, very loose, or has blood or mucus in it
- An older cat has started having accidents, especially just outside the box or on soft surfaces. Stiff joints can make a high-sided box hard to climb into. Our cat age calculator shows when your cat counts as a senior.
See our pet first aid guide for other emergency signs. Even after treatment, the habit of going elsewhere can stick, so the box changes below often still matter.
Spraying or toileting? They are different problems
Look at where and how the urine appears.
Urine marking (spraying) is communication, not a bathroom trip. The cat backs up to a vertical surface such as a wall, curtain or sofa side, lifts its tail (often with the tip quivering) and sprays a small amount. It tends to happen near windows and doors, or on new things that smell unfamiliar. A marking cat often still uses the box normally. Unneutered cats mark more, but neutered cats can mark too, usually because of stress: a new cat outside the window, a new baby, building work, a move.
Toileting outside the box means the cat squats and leaves a full-sized puddle or stool on a flat surface: rugs, bath mats, beds, laundry piles, the floor next to the box. This usually points to a medical problem or something the cat dislikes about the box.
Why cats avoid the box
The AAFP and ISFM guidelines on house soiling point to the same short list again and again.
- Not enough boxes. A common rule is one box per cat plus one extra, in different places. Two cats means three boxes. Two boxes side by side count as one to many cats.
- Box too small. Many commercial boxes are small for an adult cat. The guidelines suggest a box at least one and a half times the length of the cat, measured from nose to the base of the tail. A large clear storage tub often works better than a pet-store box.
- Dirty box. Many cats won’t step into a box that hasn’t been scooped. Scoop at least once a day and wash the box regularly with warm water and mild, unscented soap.
- Litter they dislike. Many cats prefer fine, unscented, clumping litter. Strong fragrances, box liners and deodorizers smell pleasant to people and unpleasant to some cats. A sudden switch to a new litter can also trigger accidents.
- Covered boxes. Some cats don’t mind them; others dislike the trapped smell, or feel cornered with only one way out. The cat’s opinion is the one that counts.
- Bad location. A box next to the washing machine, in a busy hallway, in a basement they rarely visit, or right beside their food bowl is easy to avoid. Cats want a quiet spot with a clear view and an escape route. In a home with several floors, put a box on each floor.
- Tension between cats. One cat may block another from the box or ambush it as it comes out, so the victim finds somewhere safer. Staring and blocking count, not just fights.
- Stress and change. Moves, renovations, a new pet or person, or an outdoor cat at the window can all set it off.
How to work out which cause applies
Spend a week keeping a simple log. Note:
- Where the mess is: vertical or flat surface, near the box or far away, near a window or door
- What it is: urine, stool or both, and roughly how much
- When it happens, and what changed around that time
- Which cat, if you have more than one. A phone camera pointed at the problem spot while you are out often answers this in a day or two.
- How your cat uses the box. Does it perch on the edge without touching the litter, dig very little, shake its paws or bolt out as soon as it is done? Those are signs the cat doesn’t like the box or the litter.
Accidents on the rug beside a covered box suggest the cat dislikes that box. Small squirts on the back door after a neighbor’s cat appeared suggest marking.
A step-by-step plan
- See the vet and follow any treatment. Tell them what your log shows.
- Clean every soiled spot properly. Use an enzymatic cleaner made for pet urine, and follow the label, which usually means soaking the area and letting it dry slowly. Don’t use ammonia-based cleaners: urine contains ammonia, and the smell can draw the cat back to the same spot. A UV flashlight in a dark room helps you find old stains you missed.
- Fix the box set-up. Add boxes until you have one per cat plus one, in separate quiet places. Use at least one large, uncovered box with a low entry, and fill it with unscented clumping litter. If you want to change litter, offer the new one in an extra box next to the old one and let the cat choose.
- Put a box where the accidents happen, for now. If your cat keeps using the spare room carpet, a box on that spot gives it a correct option. Once it is used reliably, you can move it a short distance every few days toward where you want it.
- Change the meaning of the soiled spot. After cleaning, place a food bowl, a bed or toys there, or block access for a while. Cats generally avoid toileting where they eat and rest.
- Reduce stress. The AAFP and ISFM environmental needs guidelines describe what indoor cats need: a safe place to retreat, several separated key resources (food, water, litter, scratching posts, play and rest areas), daily play that lets them stalk and pounce, predictable and gentle handling, and respect for their sense of smell. In multi-cat homes, spread resources out so no cat has to pass another to reach them. For marking near windows, block the view of outdoor cats at the lower part of the glass.
- Reward good use quietly. A calm word or a treat after your cat uses the box is fine. Most cats do not need a fuss.
Progress often takes weeks, not days. Keep the log going so you can see whether accidents are becoming less frequent.
At the moment it happens, don’t shout or chase. Let the cat finish or leave, then clean up out of sight.
What not to do
- Don’t punish. Yelling, spray bottles, swatting or putting the cat in the box as a punishment do not teach it where to go. They teach it that you are frightening, and some cats respond by hiding their accidents in harder-to-find places. The AAHA behavior guidelines advise against punishment for this reason.
- Don’t rub its nose in the mess. Cats don’t connect this with the act of peeing earlier. It only adds fear and stress, which can make both marking and bladder inflammation worse.
- Don’t scold after the fact. A cat can’t link your anger to something it did hours ago.
- Don’t clean with ammonia, or with strongly scented sprays the cat may want to mark over.
When to get professional help
Start with your vet, and go back if the problem continues after treatment and box changes. Ongoing house soiling, heavy marking or serious fighting between cats are good reasons to ask for a referral to a veterinary behaviorist, or to work with a certified behavior consultant who uses reward-based methods. When anxiety is a major factor, a vet can prescribe anti-anxiety medication where appropriate, as one part of a plan alongside changes to the home.
If your cat is also scratching furniture, our guide to cat scratching uses many of the same environmental ideas.
Sources
- 2014 AAFP and ISFM Guidelines for Diagnosing and Solving House-Soiling Behavior in Cats
- 2013 AAFP and ISFM Feline Environmental Needs Guidelines
- 2015 AAHA Canine and Feline Behavior Management Guidelines
- Cornell Feline Health Center guidance on house soiling and feline lower urinary tract disease
- International Cat Care guidance on litter trays and indoor soiling
This guide is general information and not a substitute for advice from your veterinarian or a qualified behavior professional.