ASPCA Logo

Cat Litter and Litter Boxes

Your new cat is coming home from the animal shelter tomorrow. Busily you shop, checking off the items on your list, including cat food, toys, a scratching post and myriad other goodies.

And at the very top of the list are litterbox necessities. You head to the nearest pet supply superstore, and are faced with row after row of “all things litter.” Pastel-colored clumping litter, good old clay litter, some that's made from pine and some that's made from newspaper...What to choose, what to choose? Whether you are an experienced owner or a novice, the multitude of choices could prove daunting. But this was not always the case.

Pay Dirt

Prior to World War II, most cats lived indoor/outdoor lives and their toileting areas were neighborhood backyards and gardens. For indoor needs, some families kept boxes of sand or ashes from the furnace for their cat's use in the cellar. Housewives of the 1940s were none too enamored with cats tracking ashes or sand through their homes. So an ex-sailor named Ed Lowe suggested that his neighbor try absorbent clay, which was a popular product for cleaning up industrial spills in wartime factories and happened to be made by his father's firm. Kitty Litter was born.

Granulated clay litter offered improved odor control over ashes or sand by siphoning urine to the bottom of the pan and controlling ammonia smells until the litter reached a saturation point-usually within a week in a box used by a single cat. Today, most folks either scoop solids daily and completely replace the litter once a week, or use less litter in the box and dump and clean daily. The granules of traditional litter are fairly large and do not tend to cling to a cat's paws, so there is little tracking of litter outside the box.

To Clump or Not to Clump

Granulated clay litters remained unchallenged for nearly 40 years, with little change or refinement until Thomas Nelson, Ph.D., needed a way to supplement his income while in graduate school. The biochemist began to raise Persian cats, and ended up developing clumping litter. Quoted in an October 1996 article inCat Fancymagazine, Dr. Nelson explains, “I hunted around and found clays that were dried but not baked. They were very absorbent and would form a clump when the cat urinated on them. The clump could then be removed, thereby getting rid of the urine. I had a box of litter I did not change in 10 years-I just added more-and it had absolutely no odor at all.”

The removal of almost all urine and feces does produce a better-smelling box area for weeks at a time without completely throwing out the old litter and starting from scratch. But we should point out that if more than one cat uses the box, there is usually a fairly pronounced odor in 4 to 6 weeks, even with scooping and litter replacement. It is necessary to replace the approximate amount scooped out with fresh clumping litter, for if it is allowed to go below a certain volume, urine will tend to pool and cake in corners and odors will arise.

The variety of clumping litters offers several options beyond the traditional scented and non-scented choices found with most granulated litters. Most cats prefer non-scented litter, an especially important point for owners who plan to use covered litter boxes. There are multi-cat formulas that form more cement-like clumps that will keep their form even when tread on by extra cat traffic; these are definitely not flushable! There are also less-tracking formulas, which offer slightly larger granules that are more likely to fall off of the cat's paws before he leaves the box. And there are clumping litters developed especially for flushability, a quality most clumping litters don't have due to their expansive properties. Each year the list of varieties grows.

A few years after clumping litter first came out, an article in the now-defunct holistic cat magazineTiger Tribequestioned the safety of clumping litter if ingested, especially for neonate kittens who often eat litter when it is introduced to them during the weaning stage. While there has been no proof to claims of problems in scientific literature, caretakers may wish to delay introducing kittens to clumping litter until 3 to 4 months of age. Any cat older than that detected eating litter should be taken to a veterinarian, since this behavior often indicates anemia or other dietary deficiencies.

Scoopable cat litter continues to be a hot topic on the Internet, with some claiming that it is toxic and causes respiratory illness in cats. Many scoopable cat litters contain bentonite clay, a naturally occurring clay mineral that is considered to be biologically inert when ingested, and/or silica. Silica is also a physically and chemically inert substance, and is a major component found in ordinary sand. Silica is also used as a moisture-absorbing agent in the little packets found in shoe boxes, medications and some foods. According to our experts at the ASPCA Animal Poison Control Center, pets ingesting small amounts of silica gel may develop only mild gastrointestinal upset, if any signs develop at all.

Cats may ingest small amounts of litter when grooming themselves after using the litter box, and these amounts pass through the digestive tract easily without problems. However, if an animal consumes a very large amount of litter (as can happen when a dog "cleans out" the litter box), gastrointestinal upset, constipation or, in rare cases, intestinal obstruction could potentially occur.