The 5 best cat litters for odor control and clumping

• Best cat litter overall
• Best affordable cat litter
• Best non-clumping cat litter
• Best paper cat litter
• Best multicat litter
• What else we considered
• Our cat litter testing methodology
• Types of cat litter
• Cat litter FAQs
• Check out our other great cat guides

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Cleaning the litter box is the most dreaded job of any cat guardian, but high-quality cat litter makes the task easier. What makes a person happy, however, can be the exact opposite of what a cat prefers. If the texture is wrong or the litter is perfumed, a cat may choose to do their business outside of the box. 

We set out to find the best cat litters to please both cat and guardian. To learn more about the litter preferences of cats and their toileting needs, we consulted four veterinarians. Guided by their advice, we tested 28 different litters, including clay, paper, silica gel, wood, grass, and corn substrates. Editorial review samples were provided by their manufacturers, with the exception of Dr. Elsey's Ultra Multi-Cat Strength Litter.

We tested each kitty litter for one to four weeks to evaluate its weight, shape, softness, dust, scent, clumping ability, ease of cleaning, odor control, tracking, and cost. Read more about our testing process in the methodology slide. Scroll to the end of this guide to learn more about types of litter and read our cat litter FAQs.

Read more about how Insider Reviews tests and evaluates pet products.

The best cat litter in 2023

Best cat litter overall: Tidy Cats Naturally Strong Litter (3 13.3 lb. bags) - See at Chewy
Tidy Cats Naturally Strong Litter is a clay-based clumping litter that is highly absorbent, contains odors well, and is relatively dust-free.

Best affordable cat litter: Dr. Elsey's Ultra Multi-Cat Strength Litter (40 lb. bag) - See at Chewy
Quick-clumping Dr. Elsey's Ultra Multi-Cat Strength Litter is a fragrance-free clay litter with good odor control and very little dust and tracking.

Best non-clumping litter: Pretty Litter - See at Chewy
Pretty Litter's color-changing silica gel formula is an early warning system for detecting feline urinary health problems.

Best paper cat litter: Ökocat's Non-Clumping Paper Pellet Litter (12.3 lb. box) - See at Chewy
Ökocat's Non-Clumping Paper Pellet Litter is the most absorbent of all paper litters we tested and produces virtually no dust.

Best multicat litter: World's Best Multiple Cat Litter (15 lb. bag) - See at Petco
For a natural litter that is eco-friendly, easy to clean, and odor-absorbing, World's Best Multiple Cat Litter is an excellent option.

Best cat litter overall

Tidy Cats Naturally Strong Litter is a clay-based clumping litter that is highly absorbent, contains odors well, and is relatively dust-free.

Pros: Activated charcoal controls odors; forms tight, easy-to-clean clumps; free of fragrances and dyes; lightweight; produces minimal dust; many cats prefer texture; reasonably priced

Cons: Fair amount of litter tracks outside the box

Tidy Cats Naturally Strong Litter is a dye- and fragrance-free clay-based litter with a grainy, sandy texture that most cats prefer — or at least tolerate well. It produces very little of the dust that can irritate cats with sensitive respiratory systems.

This kitty litter quickly absorbs liquid, forming a tight clump that is easy to remove in a single piece. Moistened clay was rarely stuck to the interior of the litter box. Best of all, Naturally Strong Litter contains bits of activated charcoal for odor control and was effective at preventing foul odors throughout our three-week testing period.

This litter is reasonably priced, typically averaging about 16 cents more per pound than you'd pay for a 20-pound box our budget pick, Dr. Elsey's Ultra Multi-Cat Strength Litter. The one downside: Like most clay litters, a fair amount of Naturally Strong tracks outside the box — though far less than some of the lighter weight versions we tested like Tidy Cats Free and Clean Lightweight Litter.

Best affordable cat litter

Quick-clumping Dr. Elsey's Ultra Multi-Cat Strength Litter is a fragrance-free clay litter with good odor control and very little dust and tracking.

Pros: Tight-clumping medium-grain clay litter, unscented, very little dust, low tracking, does a fine job of controlling odors, affordable

Cons: Odors can accumulate over time

Several years ago, I switched my cat to Dr. Elsey's Ultra Multi-Cat Strength Litter at the recommendation of a veterinary behaviorist, and I've been using it ever since. I was eager to see how a cheap cat litter would hold up compared to other brands tested for this guide. Quite well, it turns out.

The unscented medium-grain clay litter satisfies a cat's need to scratch, dig, and bury their waste. It produces very little dust, making it a good choice for cats with respiratory issues.

In testing, it absorbed liquid almost instantly and clumped tightly. With a bit of heft to its grains, less litter was tracked out of the box than with our top pick. A bit of a downside: This litter controls odors with 100% sodium bentonite clay rather than activated charcoal. If I'm lax on emptying and thoroughly cleaning the box every couple of months, odors begin to accumulate.

At around $0.50 per pound, Dr. Elsey's is one of the top two most cost-effective brands in this guide, along with Frisco Scoopable Unscented Litter.

Best non-clumping cat litter

Pretty Litter's color-changing silica gel formula is an early warning system for detecting feline urinary health problems.

Pros: Changes colors to monitor a cat's urinary health, made of safe silica gel, absorbs and controls odors, automatic delivery, 30-day money-back guarantee, reasonably priced, lightweight formula

Cons: Ammonia scent toward end of litter's lifespan (around 12 days for two cats), false health readings toward end of litter's lifespan (around 14 days for two cats)

Feline urinary tract diseases (FLUTD) such as bladder inflammation, urinary stones, or crystals are common in cats, according to Dr. Catherine Tannert, co-medical director of VCA Old Marple Animal Hospital, in Springfield, Pennsylvania. However, cats often hide their pain and discomfort, making it all the more challenging to figure out if there's a problem.

Pretty Litter takes the guesswork out of monitoring a cat's urinary health with its color-changing silica gel litter. When a cat's urine is too acidic, too alkaline, or contains blood, the litter changes color from a healthy yellow-green to an ominous dark yellow, blue, or red.

Both of my cats used Pretty Litter willingly, and despite its light weight, it did not stick to their feet as much as the clay litters. The litter is dust- and fragrance-free, but it does have a bit of a chemical scent.

Pretty Litter does not clump. Instead, urine is absorbed into lightweight silica gel flakes made from safe naturally occurring minerals like those frequently used in medications, food, and cosmetics. The flakes have a light, sandy texture that satisfies a cat's instinct to dig and bury their waste. Solids need to be scooped out daily.

Pretty Litter did a good job of controlling odors. The closer we got to the end of the litter's lifespan (about two weeks for two cats), the more I noticed a slight ammonia scent. Around that same time, the litter can also give false color readings. We had one stressful morning when one of my cat's urine turned blue. It turned out the only thing that was wrong was that I hadn't changed the litter fast enough.

For a single cat, a bag lasts a month before requiring changing. Pretty Litter is a subscription service priced at $22 per month for one cat. If either you or your cat isn't a fan, the company offers a 30-day money-back guarantee. 

Best paper cat litter

Ökocat's Non-Clumping Paper Pellet Litter is the most absorbent of all paper litters we tested and produces virtually no dust.

Pros: Made of sustainably sourced paper pellets, free of dyes and synthetic chemicals, very little dust, biodegradable, pellets are soft and less than 1 inch long, unscented

Cons: Expensive, some cats do not like using a pellet-style litter

Paper litters, most of which come in the form of small, firm pellets, can be good for cats with respiratory problems. Of the five paper varieties I evaluated, Ökocat's Paper Pellet Litter performed best in my first round of testing. It absorbed liquid quickly and the paper pellets did not immediately fall apart.

The pellets were the softest and smallest of the paper litters, making them more compatible with a cat's natural scratching, digging, and burying behaviors than brands with heavier, larger pellets. This litter does not clump. Instead, the paper pellets absorb as much liquid as they can before falling apart and turning into a sort of mulch. Scooping is only necessary for solids.

Neither of my cats were willing to use the paper litters, so I can't speak to how well Ökocat controls odors or holds up over time. It is clear from the weight and shape of the litter that the pellets are very low tracking compared to smaller-grained clay and natural varieties. While the litter isn't dust-free, it is close. The pellets are also biodegradable and unscented.

Ökocat's Non-Clumping Paper Pellet Litter is 35% to 60% more expensive than the other paper brands we tested. Unlike most paper litters made of recycled paper, Ökocat uses sustainably sourced dye and white paper free of synthetic chemicals. It's less environmentally friendly but better for sensitive cats.

Best multicat litter

For a natural litter that is eco-friendly, easy to clean, and odor-absorbing, World's Best Multiple Cat Litter is an excellent option.

Pros: Made from compressed corn kernels, similar texture to clay litters, controls odors well when cleaned frequently, minimal dust, reasonably priced

Cons: Odors can build up without frequent cleaning and become more noticeable around three weeks of use by two cats

Thanks to its good clumping ability and odor control, World's Best Multiple Cat Litter came out on top of the 12 natural litters we tested. Its lightweight granules are made from compressed corn kernels. They are slightly harder than those of the clay litters in our best overall and best budget cat litter categories, but they are still satisfyingly scratchable for cats.

World's Best absorbed liquids instantaneously to form tight, solid clumps that maintained their shape and structure during removal. The litter's natural corn-cereal scent controlled odors well when cleaned twice a day. However, I found if I left clumps in for 24 hours, the scent of ammonia became increasingly strong. In the last few days of our three-week testing period, the remaining litter in the box was somewhat less effective at absorbing odors than it had been in the beginning. Based on this observation, I would expect that by the end of four weeks, ammonia odors are likely to be even more noticeable. 

Tracking of this litter is relatively minimal — about equivalent to our top clay litter selections. The litter is also free of synthetic additives, chemicals, and fragrances and produces very minimal dust. A 15-pound bag of Multiple Cat Litter should last about a month for two cats. 

What else we considered

What clumping clay litters we also recommend

• Cat's Pride Unscented Natural Care Multi-Cat Clumping Litter: This affordable cat litter absorbed liquids instantaneously and formed clumps that were only a little more likely to break apart during cleaning than our top picks. It's more likely to be tracked than heavier litters. For every 15-pound jug purchased, the company donates a pound of litter to an animal shelter.
• Tidy Cats Free and Clean Lightweight Litter: This litter was on par with the brand's Naturally Strong variety, which we selected as the best cat litter overall. It absorbed liquids on contact, clumped tightly, controlled odors with activated charcoal, and produced very little dust. However, it tracked more than the Naturally Strong litter, with granules of litter sometimes riding on my cats' feet all the way to the living room couch.
• Frisco Scoopable Unscented Litter: Frisco's Scoopable Litter is a steal. It controls odors as well as our best affordable litter pick, Dr. Elsey's Ultra Multi-Cat Strength Litter, but is less instantaneously absorbent, forming thinner and more fragile clumps that spread more widely across the pan. That said, it's unscented and among the least dusty formulas, making it a great option for anyone looking to save a few bucks.

What clay clumping litters we don't recommend

• Arm & Hammer Unscented Multi-Cat Litter: Although it is advertised as unscented, this litter has a light laundry detergent odor. It formed solid clumps but was the dustiest of all of the litters we tested.
• Pioneer Pet Smart Cat Lightweight Clumping Litter: This lightweight, unscented litter absorbs liquid and clumps well, but the moisture that escaped to mix with clay at the bottom of the pan was surprisingly challenging to remove.
• Cat's Pride Scented Bacterial Odor Control Multi-Cat Litter: The litter produced very little dust and clumped reasonably well, but it didn't capture all of the liquid, leaving wet clay stuck to the bottom of the pan. It also has a light soapy scent.
• Arm & Hammer Cloud Control Litter: Arm & Hammer's Cloud Control was the least absorbent litter out of the nine clay varieties, although what liquid it absorbed clumped solidly. A heavy litter perfumed with a light laundry scent, Cloud Control is, at the very least, dust-free.

What non-clumping litter we also recommend

• Petsafe Scoop Free Scented Crystal Litter: Lightly scented and with very little dust, this crystal litter absorbed moisture and captured odors. Like Pretty Litter, Petsafe's non-clumping crystal litter is made from silica gel and a single bag lasts up to 30 days for one cat. Ultimately, Pretty Litter won in this category because it signals when a cat might be experiencing urinary trouble.

What paper cat litter we don't recommend

• We'd tested three different paper litters from Yesterday's News, but they have since been have been discontinued by Purina. 
• Frisco Paper Pellet Non-Clumping Cat Litter: Frisco's paper litter contains baking soda for decent odor control and gives off minimal dust. However, its long, hard pellets made it one of the least conducive to a cat's natural scratching and covering behaviors.

What natural cat litters we also recommend

• Pioneer Pet Smart Cat Clumping Grass Litter: This grass litter acted almost exactly like a good clay clumping litter. The particles absorbed moisture instantly and formed strong, solid clumps. Soft to the touch, essentially dust-free, and odor-trapping, the only thing keeping this litter from the top spot was its cost — almost double the equally effective World's Best Multiple Cat Litter.
• World's Best Original Unscented Cat Litter: Made from corn and with very little dust, World's Best Original Cat Litter absorbed liquid moderately well and formed relatively solid clumps.
• World's Best Zero Mess Cat Litter: My cats and I both liked the Zero Mess litter, which blends corn kernels with additional plant fibers to absorb liquid and form tight clumps. It did a great job of minimizing odors. However, it worked no better than World's Best Multiple Cat Litter despite costing around 25% more.
• Ökocat Super Soft Wood Litter: This litter did an excellent job of absorbing liquids and preventing odors. It also had a superior clumping ability as opposed to Feline Pine and Okocat's Original Litter — though clumps were more likely to fall apart in cleaning than some of the other natural litters. My cats seemed to prefer the softer, smaller granules and toileted in it a little more frequently than the other wood litters, though not as often as the grass, walnut, or grain varieties.

What natural cat litters we don't recommend

• Frisco Corn and Wheat Cat Litter: I was disappointed by this litter's absorbency. Not only did liquid spread out within the litter, but it also seeped all the way to the bottom of the pan and left it wet. The clumps that did form were also quick to fall apart, making this litter more challenging to clean.
• Frisco Clumping Grass Litter: Relative to Smart Cat's All Natural Clumping Grass Litter, Frisco's formula did a worse job at absorbing moisture into tight clumps, making them more of a challenge to remove.
• Ökocat Original Wood Clumping Litter: Ökocat's original clumping formula is made of the same sustainably sourced wood as the Super Soft Clumping style and it absorbs moisture just as quickly. But this litter's clumping ability was disappointing. It stuck together in some places, while in others, the wood granules quickly degraded. When dry, those same granules are quite sharp and stiff, a texture that sensitive cats may prefer to avoid.
• Feline Pine Clumping Wood Litter: Made of reclaimed lumber shavings, this was the softest of the wood litters, but it was also the dustiest. I was also unimpressed with its clumping ability. It absorbed moisture slowly and turned mealy like oatmeal instead of forming a solid clump.
• Naturally Fresh Quick-Clumping Walnut Litter: This clumping formula was my least favorite of the walnut litters. It absorbed liquid well, but its clumping ability was just okay. Many of the clumps fell apart and were more challenging to remove. It was also the dustiest of the three nut-shell varieties.
• Naturally Fresh Multi-Cat Ultra Odor Control Walnut Litter: Like Naturally Fresh's Quick-Clumping Litter, Multi-Cat is a harder, rockier substrate than Littermaid's walnut litter and its clumping ability was fair but not great. This formula also left the most clumped litter stuck to the interior of the litter pan.

Our cat litter testing methodology

I tested the cat litters in two phases: a pre-cat phase and a cat phase. First, I compared litters belonging to the same category in heats of four at a time, assessing them for a variety of factors, including clumping ability, dustiness, scent, and texture.

The top two litters in each heat went on to the next phase. Each one was poured into a litter pan for the cats to use for anywhere from one to four weeks to test for odor control and tracking. Litters that were tested for two weeks or less were those that my cats refused to use or those we tested prior to receiving the bulk of the litters for this guide. For each litter, I considered the following qualities:

• Litter weight, shape, and softness: Cats typically prefer a soft, grainy litter that is easy to dig, so I evaluated the shape, texture, softness, and density of each litter. I measured 1/4 cup of each on a kitchen scale to compare their weights.
• Dust and scent: Cats are sensitive to both dust and scent, so I measured the relative intensity of each. I noted the amount of dust emitted when pouring and scooping the litter, as well as how much peppered the sides of the bowl or litter box.

  For scent, I went by the advice of Dr. Catherine Tannert, co-medical director of VCA Old Marple Animal Hospital, who said, "Cats prefer unscented litter to the cloying smell of kitty litters that are developed for the owner's perception of cleanliness." I did a sniff test of each litter in both phases of testing, including the thankless job of lifting clumps of litter to my nose to gauge how much of an ammonia scent they emitted.

• Clumping ability and ease of cleaning: In phase one testing, I compared a small amount of each litter in plastic bowls with slick interiors similar to a litter pan. I added 1/4 cup of water to each bowl in two separate trials to gauge how quickly and easily it was absorbed, as well as how solidly it clumped and stuck together upon scooping. At the end of both trials, I emptied each bowl to look for moisture that had escaped the clumps and adhered to the bottom of the bowl.
• Odor control and tracking: The top two litters from each category went on to phase two testing in a litter box for one to four weeks. I cleaned the litter pan twice daily, noting how easy clumps were to remove and how much ended up on the floor. A daily sniff test determined whether odors were under control. Because my cats refused to use the paper litters, I was unable to complete a phase two test on them.
• Cost: I calculated the cost per pound of each litter and compared them. With lightweight clay litters, I first calculated their weight relative to a standard clay litter and adjusted the price accordingly.

Types of cat litter

Clay litter

Nearly every one of the more than a dozen veterinarians, veterinary behaviorists, and cat specialists I've spoken to about cat toileting behavior agrees that most cats prefer, or are at least more tolerant of, nonperfumed clay litters. "Generally speaking, I recommend a fine-grained, clay-based clumping litter that is unscented," said Dr. Karen Sueda, veterinary behaviorist at VCA West Los Angeles Animal Hospital. 

Most clay cat litters are made from absorbent sodium bentonite clay, a naturally occurring material acquired through strip-mining and broken down into pebble-sized granules. Some clay litters are mixed with activated charcoal for additional odor absorption. They come in both unscented and scented varieties. Traditional clay litters are also quite dusty when poured, scratched at by a cat, or cleaned, though many newer formulas produce very little dust.

Pros: Preferred or tolerated by most cats because they make practicing natural toileting behaviors like digging and covering waste easy; absorb liquids instantly and form tight clumps for easy cleaning; control odors, especially those formulas that contain activated charcoal; cost efficient; some formulas are virtually dust free

Cons: Weigh more than some other varieties of cat litter; are produced in an environmentally unfriendly way; scented formulas can be too strong for a cat's sensitive nose; can be easily tracked out of the litter boxes, especially lighter weight formulas; some formulas are very dusty

Paper litter

For cats that suffer from respiratory problems like asthma or have recently undergone surgery, Dr. Zay Satchu, chief veterinary officer at Bond Vet, typically recommends a paper litter, which tends to be less dusty than clay litters and less likely to stick to incision sites.

Most paper litters come in pellet form and are made from either recycled materials or sustainably sourced wood. They are also almost always non-clumping with pellets that absorb liquid and slowly break apart over time. Only solids need to be scooped out of a litter box filled with paper litter.

Pros: Good for cats with respiratory problems, only solids need to be scooped from the litter box, pellet formulas are low-tracking, made from recycled or sustainably sourced materials

Cons: Some cats dislike the texture and weight of paper pellets, pellets fall apart over time, odors may increase over time as pellets become saturated with urine

Silica gel litter

Silica gel or crystal litters are made from sodium silicate sand, a naturally occurring material acquired through strip mining. They do not contain crystalline silicate or other carcinogenic materials that may be harmful to cats, but the inhalation of microscopic silica dust over time could lead to respiratory issues.

Silica gel litters are ultra-absorbent odor-eaters, but as the non-clumping granules saturate with urine over time, they may become less effective at preventing ammonia odors. Some silica litters, particularly crystal versions, may be too sharp for sensitive paws.

Pros: Made from safe, natural silica gel; ultra-absorbent and good at preventing odors; non-clumping formula does not require removal of liquids

Cons: Inhalation of silica dust over time may lead to respiratory issues, crystal formulas may be too sharp for sensitive paws, smells can worsen over time as silica gel becomes saturated with liquids, not environmentally friendly

Natural litter

Grain, grass, wood, and walnut shells are all used as alternative materials in natural cat litters. According to Satchu, not only are these biodegradable options more environmentally friendly, some have additional benefits too. Due to their absorption ability, wood litters are typically low tracking and do a good job minimizing odors while grain litters are a safe bet for cats who like to snack on litter due to behavioral issues.

Ultimately, the superiority of one style of natural litter over another comes down to a cat's individual preference. "I try to encourage owners to choose one litter and stick with it through kitty's life because they are ultimately creatures of habit," said Satchu. "Any litter that will keep kitty going where they're supposed to be going is a good litter in my book."

Pros: Many formulas are low dust, natural scent of some varieties controls odors without additives, biodegradable, made from sustainable materials  

Cons: Some cats may dislike the scent and/or the texture of natural litters, lightweight formulas are more easily tracked than heavier clay litters, more expensive on average than clay litters

Cat litter FAQs

What type of cat litter is best?

Litter preferences vary from cat to cat, according to Dr. Karen Sueda, veterinary behaviorist at VCA West Los Angeles Animal Hospital, but every feline wants a toileting substrate they can easily dig and cover their waste in. Cats with sensitive feet may avoid using litters with sharper granules, such as crystal or pellet formulas.

What is the difference between clumping and non-clumping litters?

Clumping cat litters, including those made from clay, corn, wood, and grass, form solid masses when they come into contact with urine, and those must be removed from the litter daily.

Non-clumping litters absorb urine, but instead of forming clumps, the granules of silica, wood, or paper become saturated and gradually break down over time. On each cleaning, the substrate must be stirred to distribute the ammonia in the box. There is no difference between how non-clumping and clumping litters interact with solids — feces must still be scooped daily.

Both clumping and non-clumping litters manage bad smells. In the case of clumping formulas, urine is removed through daily scooping. In non-clumping formulas, urine accumulates in the box over time. Clumping litters can be topped off with additional litter as needed, but boxes filled with a non-clumping litter must be completely emptied and refilled after a period of two to seven weeks, depending on the brand and type of litter.

Is there a dust-free cat litter?

Dusty natural and clay litters can be problematic for both cat and human. Dust may cause sensitive cats, particularly those with allergies or respiratory issues like asthma, to cough, sneeze, or wheeze during or after using their litter. It can produce the same effect in humans when filling or scooping the box. While no litter is completely dust-free, those that produce very little dust are less likely to have unintended respiratory effects.

Is fragrance-free cat litter better?

Because cats have an extremely strong sense of smell, the scent of a litter is a significant factor in whether they will use or avoid a litter box, according to Dr. Christine Calder, veterinary behaviorist at Midcoast Humane. Even a natural scent may deter a cat. Calder, Sueda, and Tannert all recommended sticking to an unscented variety.

Is flushable cat litter actually flushable?

One of the purported benefits of some natural cat litter varieties is that they can be flushed in the toilet. But just because you can flush natural cat litter doesn't mean you should, and not just because low-flush toilets and pipes made for human waste often can't handle clumps without clogging.

Cat waste can contain Toxoplasma gondii, a parasite that causes flu-like symptoms at best and, at worst, fetal development disorders, brain damage, and premature birth in babies. Water waste treatment plants are unable to filter out this harmful parasite and it can end up in treated water that's released back into the environment, harming fish, killing native plants, and making recreation areas unsafe. Scientific studies have found that T. gondii especially poses a threat to marine mammals like sea otters.

How many times a day does a cat normally use the litter box?

On average, cats urinate two to four times a day, but according to Sueda, this can vary from cat to cat. Cleaning litter boxes at least once daily can help guardians determine if there's a change in frequency, which may indicate a health problem.

Typically, cats defecate one to two times a day, but this, too, can vary from cat to cat. Like with urination, sudden changes in frequency may indicate a health problem.

What size and how many litter boxes do I need?

A litter box should be at least 1.5 times the length of a cat, large enough for them to comfortably scratch and bury their waste. The standard rule of thumb is to have one litter box per cat plus one extra, and ideally one on each floor of a home. A home with multiple cats, however, may be able to get away with fewer extra-large litter boxes as long as they are cleaned at least twice a day, according to Sueda. See our guide to the best litter boxes for more on this.

What does it mean if a cat stops urinating?

If a cat stops urinating altogether, it is likely they are experiencing a feline urinary tract disease (FLUTD) such as bladder inflammation or urinary stones or crystals. Male cats are particularly susceptible to the latter. "Male cats have a very narrow urethra, so crystals and mucus can form a plug or a single tiny stone may become lodged anywhere along this narrow tube," said Tannert.

If a cat is unable to urinate, deadly toxins begin building up. Death can occur if the blockage isn't removed by a veterinarian within 24 to 48 hours. If a veterinarian rules out medical problems like FLUTD, anxiety may be the culprit, a problem a veterinary behaviorist is best equipped to handle.

What does it mean if a cat goes outside the litter box?

According to Calder, cats that eliminate outside the litter box are engaging in one of two behaviors: toileting or marking. In toileting (also called inappropriate elimination), a cat has found a place to do their business outside of the litter box. Sometimes, this behavior occurs when a cat does not like the location or size of their litter pan, the type of litter in the pan, or the cleanliness of the litter.

Other times, going outside the box is related to anxiety (for example, a cat who worries about being ambushed by another pet while using the litter box may stop using it altogether) or to a medical problem such as FLUTD. A cat may also choose to go outside of the litter box if they find a spot that satisfies their need to scratch and bury their waste, such as a pile of dirty laundry or a potted plant.

Whereas toileting typically occurs on horizontal surfaces, marking occurs on vertical surfaces. Instead of squatting, when a cat marks they back up with a raised tail to spray their pheromones. "Marking cats are trying to communicate something, and most have some kind of conflict or anxiety," said Calder. Cats that mark are typically intact males, but fixed males and females can spray, too.

Check out our other great cat guides

• The best cat litter boxes
• The best cat food for kittens, adult cats, and seniors
• The best cat toys
• The best products to protect your furniture from cat scratching
• The best automatic cat feeders for wet and dry food
• The best cat carriers
• The best airline cat carriers
• The best cat brushes
• The best flea preventives and treatments for cats
• The best online veterinary services for your pets
• The best cat harnesses
• The best cat collars
• The best cat toothpaste, toothbrush, dental treats, and water additive
• The best interactive cat toys
• The best cat dewormers

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