Why Do Cats Stop Using the Litter Box?

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Why do cats stop using the litter box? The ASPCA and Humane World guidance reviewed for this guide points to a few common causes: a medical problem that makes the box painful or urgent, a box or litter the cat does not like, a box in a location it dislikes, conflict with another cat in the home, or a frightening experience while using the box. Because a medical problem can be behind a sudden change, the sources put a vet check first. This guide sets out the causes the sources describe and the steps they recommend.

Quick answer

• A cat that stops using its box usually has a reason tied to its health, the box, the litter, the location, another cat, or a frightening experience.
• Medical problems come first in the sources, so a sudden change should be checked by a vet.
• Scoop at least once a day, since the ASPCA says virtually all cats like clean litter boxes.
• Place boxes in a quiet spot that is accessible and not cornered, away from high-traffic areas.
• Provide one box for each cat in the home, plus one extra, as the ASPCA recommends.

Step 1: Rule out a medical problem

The ASPCA describes medical causes of litter box avoidance and says the first step is to rule out both medical problems and urine marking. It gives urinary tract infection as an example: a cat that visits the box often but passes only small amounts of urine may have one. The ASPCA advises seeing a veterinarian to rule out this kind of problem.

The ASPCA adds that a cat whose medical condition caused pain while eliminating may learn to associate that discomfort with the box and avoid it, even after the health problem has been treated. General guidance: if the change is sudden, or the cat strains, cries, or repeatedly goes back to the box without producing much, ask a vet before changing the setup.

Step 2: Check the box and the litter

The ASPCA says that if a cat is not comfortable with its box or cannot get into it easily, it is unlikely to use it. The ASPCA also says that the cat may dislike a particular box type or the litter itself. Cornell’s house-soiling guidance says any medical condition that interferes with normal urination or defecation can cause litter box problems, and lists kidney and thyroid disease and diabetes among the possible causes. Humane World’s guidance says a good box is large enough for the cat to turn around comfortably and low enough for easy entry and exit.

The ASPCA recommends switching to a box with low sides if entry is a problem. For a cat that starts avoiding a self-cleaning box, the same guidance suggests trying a traditional box. General guidance: when changing litter, make the switch gradual rather than sudden, since an abrupt change can put a cat off the box.

For where to place the box, see where to put a litter box. General guidance: scoop at least once a day, and wash the box regularly with mild soap and water, rinsing well so no strong scent is left behind. Cats are sensitive to odors, so avoid heavy cleaning scents near the box.

Step 3: Look at the location

The ASPCA says that cats develop preferences about where they eliminate and may avoid places they dislike. If the box is in a spot the cat finds unpleasant, it may avoid it. The ASPCA recommends a location that is quiet but not cornered. Humane World advises a quiet, low-traffic but accessible place away from food and water.

The ASPCA also advises placing boxes away from high-traffic areas and away from places where the cat might feel trapped. Humane World warns that while it can be tempting to hide a box in an out-of-the-way spot, owners should avoid spots that feel unsafe or uncomfortable for the cat. A box tucked into a dead end can feel like a trap, especially in a home with other animals.

Step 4: Address conflict between cats

The ASPCA lists conflict between multiple cats in a home as one reason elimination problems develop. A cat that is guarded by another cat may avoid a box in its path. The ASPCA advises one box for each cat in the household, plus one extra, and says each cat should also have adequate resting areas.

General guidance: if two cats share a home, watch whether one cat waits outside a box or chases the other away from it. Placing boxes in different rooms can help when the boxes sit close together.

Step 5: Consider a frightening experience

The ASPCA explains that a cat that was startled, cornered or trapped while using its box can associate the box with that event and avoid it afterward. Things that can upset a cat in its box include being cornered by a dog, cat or person, hearing a loud noise or commotion, or seeing something frightening or startling.

The ASPCA’s suggested approach is to make the box feel safe again. That can mean a box in a calmer location, a litter that is a little different from the one the cat avoids, and no punishment. The ASPCA specifically warns against rubbing a cat’s nose in urine or feces.

Step 6: Act early

The ASPCA notes that once a cat avoids its litter box, the avoidance can become a chronic problem. The cat may develop a surface or location preference, such as a rug or a favorite chair, which is harder to change later. This is one reason to respond quickly to a new habit rather than wait for it to resolve on its own.

General guidance: keep a short log of when the cat uses the box and when it does not. A pattern in the log can help a vet or behavior professional see whether the problem is medical, environmental or social.

Step 7: Know when to get help

The ASPCA points owners toward professional behavior help when a problem persists. A vet can rule out medical causes, and a behavior professional can help when the cause appears to be stress, conflict or a learned association. For cleaning routines, see how to clean a litter box. General guidance: if the cat stops using the box entirely, passes blood, strains, cries in pain or loses weight, ask a vet promptly.

How we chose

We limited this guide to the ASPCA, Humane World and Cornell pages we opened on 2026-10-27. We kept what those pages state directly and marked the rest as general guidance.

What we could not verify

• The sources do not say how long a cat takes to return to its box after a fix, and that timing varies between cats.
• The sources do not name one litter type that works best for every cat.
• The sources do not give a cleaning schedule beyond scooping, so the washing schedule above is general guidance.
• The sources do not say whether a particular box size or depth fixes a particular problem.
• Product choice is outside the scope of these sources and is not covered here.

FAQ

Why did my cat suddenly stop using the litter box?

A sudden change can come from a medical problem, a change in the box or litter, a new pet or person in the home, or a frightening event. The ASPCA says to rule out medical causes first. Ask a vet if the change is sudden.

Does a dirty box cause a cat to stop using it?

The ASPCA says cats generally like clean litter boxes and recommends scooping at least once a day. General guidance: wash the box regularly as well.

Should I change the litter if my cat avoids the box?

Change slowly. General guidance: mix a little of the new litter into the old and increase the proportion over several days.

Can another cat cause my cat to avoid the box?

Yes. The ASPCA lists conflict between cats as one cause and recommends one box per cat plus one extra.

What if my cat is going on a rug instead of the box?

The ASPCA warns that a cat can develop a surface preference if avoidance continues. Ask a vet first to rule out a medical problem, then clean the spot thoroughly and make the box more appealing.

When should I see a vet?

Ask a vet if the change is sudden, if the cat strains, passes blood, cries in pain or loses weight, or if the problem continues after you have checked the box, litter and location.

Bottom line

A cat that stops using its litter box is usually telling you something about its health, the box, the litter, the location, another cat or a bad experience. The ASPCA and Humane World both put medical causes first, so a sudden change deserves a vet check. Once a health problem is ruled out, scoop daily, keep the box clean and comfortable, place it in a quiet and accessible spot, and provide enough boxes for every cat in the home. For any sign of pain or illness, ask a vet.

Sources

• ASPCA, Litter Box Problems: https://www.aspca.org/pet-care/cat-care/common-cat-behavior-issues/litter-box-problems (opened 2026-10-27)
• Humane World for Animals, How to Litter Train a Kitten or Cat: https://www.humaneworld.org/en/resources/how-litter-train-kitten-or-cat (opened 2026-10-27)
• Cornell Feline Health Center, Feline Behavior Problems: House Soiling: https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-behavior-problems-house-soiling (opened 2026-10-27)