Litter boxes are sacred spaces for cats. When cats refuse to use their litter, it can be a sign of an underlying illness. It can also indicate fear, anxiety, discomfort, or even pain due to unfavorable bathroom conditions.
Cat owners can choose from over a dozen types of litters and many more litter boxes. Which are best depends on an individual cat’s needs. Considerations such as respiratory health, paw sensitivities, mobility, and general preference should all influence the decision.
Note: Cats who suddenly change their bathroom behaviors should see a veterinarian as this can be a sign of a serious health issue including urinary tract illness.
First, let’s consider the main health, safety, and comfort issues for cats regarding bathroom areas:
Respiratory health and scent sensitivity: Cats are down in the litter—as close as they can possibly get. They have sensitive noses that are far more powerful than human noses. Perfumes and heavy dusts in some litters can overwhelm noses and harm respiratory systems. Cats with asthma and other respiratory issues are especially sensitive.
Age and mobility: Kittens, seniors with arthritis, and cats with disabilities or mobility issues may find some litter boxes difficult or painful to navigate in and out of.
Size: Cats should have enough space to comfortably fit in their boxes and move around within their bathroom spaces.
Ingestion: Most litters contain ingredients that are harmful when ingested in large amounts; but some litters are made of substances that some cats find impossible to resist eating.
Anxiety: Some litter boxes have features that can cause anxiety in cats for several reasons.
Paw pain: Litter material and size can affect how litter feels to cats’ paws. Some can cause discomfort and pain, especially to declawed cats.
Litter material
Let’s look at the most common types of litters and their attributes. All one come in clumping and non-clumping varieties.
Clay
Clay litter is the most used litter and seems to be the preferred choice for most cats. It comes in fine to medium-sized grains, which is easy on cats’ paws. Qualities customers appreciate:
- Affordability
- Familiarity
- Easy cleanup (clumping varieties)
- Cat preference
When choosing this type, opt for low dust and fragrance-free. Perfumes may help mask odors, but they can be off-putting to pets and harmful to their lungs.
Studies show breathing crystalline silica dust, found in some clay and silica litters, can be harmful to pets and humans. Read labels carefully. Litters labeled as low dust are less likely to have crystalline silica*.
*Note: crystalline silica is not the same as amorphous silica gel.
Silica
Silica sand and crystal grains vary in size from very fine to very large. Qualities customers appreciate:
- Absorbent
- Controls odor
- Low tracking
- Some formulas indicate a change in urine pH by changing colors
Stepping on larger silica crystals can be uncomfortable or painful to cats’ paws. Silica can also irritate some cats’ paws. While color-changing silica litter can be a tool to indicate a change in urine pH, it shouldn’t replace veterinary advice or regular checkups.
When choosing this litter, opt for low-dust and fragrance-free varieties made with amorphous silica gel. Your cat may prefer small crystals.
Wheat, corn, and walnut
Desirable qualities:
- Lightweight
- Soft on paws
- Environmentally friendly
These can cause allergies in some cats. Some cats will eat these litters, confusing them for food products. They can also attract pests and become moldy; and mold in corn litter can produce dangerous substances called aflatoxins.
Pine and wood
The clumping varieties of pine and wood litters are soft and easy on paws. The pellet varieties can be hard and uncomfortable to cats’ paws. The heavy smell of pine litter can also overwhelm cats.
Paper
This litter does not come in clumping varieties and is the least likely to control odor well. However, paper litter is soft, light, and environmentally friendly. It’s a good choice for cats with sensitive paws or those with post-surgical wounds that need to be kept clean and dust free.
Litter boxes
Litter boxes are just as important as what’s in them, and there are many from which to choose. Here are some ways common features may affect cats’ bathroom experiences.
Small boxes
Save these for the kittens.
- Cats should be able to sift through, sit, and turn around without touching the sides
- Boxes should be 1.5 times the length of the cat from base of tail to nose
Self-cleaning boxes
Cats are sensitive creatures and can become anxious easily. They generally prefer quiet, roomy spaces with good visibility in which to do their business.
- Noise of self-cleaning boxes can frighten cats
- Many are too small inside
- Those with enclosed spaces trap dust, odors, and perfumes
- It’s difficult to notice changes in urine and feces that can indicate illness
Covered boxes
Owners may choose this type of box to reduce odor, tracking, or give cats privacy. While some cats don’t mind covered litter boxes, others become anxious. If you choose this type, opt for the largest one possible and remove the front flap. Other considerations:
- While they prefer quiet spaces, it’s a misconception that cats want privacy while using the litter box
- Cats feel secure when they can see their surroundings, and covered boxes limit cats’ visibility
- Most covered boxes tend to be too small
- Covered boxes trap dust and odors
- Flaps on covered boxes can scare cats
Top-entry boxes
Top-entry boxes are essentially tall, covered boxes that have entrances on top instead of in front.
- They tend to be small and restrictive
- They are challenging for kittens, seniors, and cats with mobility issues
- As with other enclosed boxes, these can cause cats in multiple-cat households to feel unsafe
High-sided boxes
High-sided, open-top boxes are good options for cats that scatter litter while using the box. They also allow plenty of visibility and ventilation. For seniors and those with mobility issues, opt for ramps or boxes with low entrances.
You can even create your own litter box by cutting an entrance into a plastic storage tote. Be sure to sand down any sharp edges.
Other tips for creating a comfortable, safe bathroom environment for cats:
- Use enough boxes: one per cat plus one
- Consider adding splash guards to litter boxes if appropriate and tolerable for cats who spill litter or urinate high up
- Keep litter and boxes clean for comfort and health
- Place litter boxes in quiet places (away from noisy appliances and lots of foot traffic)
- Place boxes in separate areas in multiple-cat households to discourage resource hoarding/bullying
- Avoid using scent crystals and other fragrance additives
- If you notice any change in behavior, contact your veterinarian to rule out illness and to discuss solutions
References:
Center for Veterinary Medicine. Aflatoxin poisoning in pets. U.S. Food And Drug Administration. Published August 19, 2024. https://www.fda.gov/animal-veterinary/animal-health-literacy/aflatoxin-poisoning-pets
Drent M, Wijnen PA, Boots AW, Bast A. Cat litter is a possible trigger for sarcoidosis: Figure 1–. European Respiratory Journal. 2011;39(1):221-222. doi:10.1183/09031936.00074411
Grigg EK, Pick L, Nibblett B. Litter box preference in domestic cats: covered versus uncovered. Journal of Feline Medicine and Surgery. 2012;15(4):280-284. doi:10.1177/1098612×12465606
Is silica cat litter toxic? VetInfo. https://www.vetinfo.com/silica-cat-litter-toxic.html
Iwabuchi-Inoue Y, Hattori Y, Kikusui T. Litter box size and litter type preference and their associated behavioral changes in cats. Journal of Veterinary Medical Science. 2025;87(6):614-620. doi:10.1292/jvms.24-0468