Clumping Clay Kitty Litters: A Deadly Convenience?

Clumping Clay Kitty Litters: A Deadly Convenience?

“. . . something able to block household plumbing must be wreaking havoc on the plumbing of our feline companions.”

Cats die. Kittens die. It’s part of life. But we still grieve when they die, even though we know it is only the body, not the spirit, that is gone. How much worse we feel when those deaths were unnecessary, could have been prevented by something as simple as changing the kind of litter we use.

I breed Japanese Bobtail cats and I grieved in 1994 when an entire litter of kittens (born in November 1993) died. Despite round-the-clock nursing and force-feeding of fluids and food, one kitten, then another, let go of his grasp on life.

The three kittens started out as a robust, lively group. Then, at weaning time, just as they were learning to use the litter box, they began to vomit a yellow frothy substance and to pass yellow diarrhea; the diarrhea looked and smelled like clay. They also had nasal and eye discharge. The diarrhea proceeded to turn harder and even more clay-like, and finally the kittens stopped moving their bowels at all. The veterinarians said they could feel “a hard mass” inside. The kittens dwindled into thin, dehydrated, frail little skeletons, sunk in apathy. Then they died.

When these kittens first fell sick, I wasn’t too worried, because I had seen the same set of symptoms in two earlier litters. The first time it happened I’d lost one kitten, but the other survived with a week of force-feeding fluids. When a second litter started to exhibit the same symptoms, we took the kittens and their parents to the veterinarian, who tested them for everything from intestinal parasites to feline AIDS. The results were negative. “Some kind of virus” was the vague diagnosis, or “possibly giardia” (an intestinal parasite), even though the test for it was negative. We nursed them, gave them fluids and love, and like the previous kittens, these two were over the problem in a week.

So the third time, with the November kittens, although I was a little worried, I was confident we could pull these through as well. But their illness dragged on for three weeks, and they grew progressively weaker. Again we had the cats and kittens tested for a variety of problems; again, nothing. And then, all within the same week, the kittens died.

When a fourth litter, born in late March 1994, began to exhibit the same symptoms yet again, I felt frustrated, frightened, and helpless. What was going on? Was there something in the environment? Was my home somehow a “sick house?” Was one of the adult cats carrying something that the kittens were picking up? I always keep my cats indoors, so it couldn’t be exposure to outside cats.


I decided I needed a new perspective and began to look for a holistic veterinarian. The next day, a friend gave me the card of a new holistic veterinarian in town, Dr. Stephanie Chalmers.

But before I had the chance to take the kittens to see this new vet, I was struck by a bolt of lightning. The clumping litter! It was almost as though someone had whispered it into my ear. It made perfect sense. Everything fit; it explained all the symptoms. My thinking went along these lines:

  1. Clumping litter is designed to form a hard, insoluble mass when it gets wet. It also produces a fine dust when stirred (as when a cat scratches around to bury a recent deposit). And these clumping litters absorb many times their weight in fluids.
  2. When cats or kittens use the litter box, they lick themselves clean; anything their tongues encounter gets ingested. Kittens especially tend to ingest a lot of litter when they are first learning to use the box.
  3. Once the litter is inside a kitten or cat, it expands, forming a mass and coating the interior-thus, both causing dehydration by drawing fluids out of the cat or kitten, and compounding the problem by preventing any absorption of nutrients or fluids.

My cats and kittens had probably reacted with diarrhea initially in an effort to cleanse their bodies of the litter before it had a chance to settle and coat their insides. But kittens have very small intestines; a hard insoluble mass could very well produce a complete and fatal blockage within a couple of weeks.

On the strength of these deductions, I immediately went out and bought a plant-based litter to replace the clumping litter. I also took several of the hard, clay-like lumps of stool produced by two of the kittens and smeared them open. Not only did the stools have the consistency, smell, and texture of clay, but they even retained the color of the litter (gray with blue flecks) inside. This was confirmation enough for me.

As soon as I could, I took all the kittens, along with their mother, to Dr. Chalmers, who said that she had already heard of problems like this with the clumping clay litters. She put the kittens on a holistic course of treatment (slippery elm to help soothe the intestines; homemade chicken broth to nourish the kittens without putting further strain on their insides).

She also showed me an article by Lisa Newman, another holistic health practitioner, citing some of the cases of illness and death that she (Lisa Newman) has seen first hand—illnesses and deaths most likely caused by clumping litter. A light went on in my head when I read the following:

“There has been a rise in depressed immune systems, respiratory distress, irritable bowel syndrome, and vomiting (other than hair balls) among cats that I have seen in the past two years. All had one thing in common…a clumping product in their litter box. In several cases, simply removing the litter improved the condition of the cat.” (“Great Clumping Cat Litter—Is That Why Kitty is So Sick?Healthy Pets—Naturally, April 1994.)

The problem of health difficulties and even deaths resulting from clumping litters appears to be more prevalent than most people are aware of. I recently spoke with another Japanese Bobtail breeder, who told me of a kitten she sold that subsequently became very ill with a severe respiratory problem. The new owner used a clumping litter, and her veterinarian found that the kitten’s lungs were coated with dust from the litter.

For a veterinarian to spot this problem is unusual. A more common diagnosis would lay the blame at the door of a virus, germ, fungus or parasite. There is not a general awareness yet that the clumping litters can be harmful—even fatal—to cats.


And the problem extends beyond cats. As Lisa Newman points out in her article, dogs get into the litter box for “snacks,” and ingest the litter too. She reports that the autopsy of one dog revealed that his stomach was filled with the clumping litter.

An article entitled “How Cat Litter is Made” appeared in Cat Fancy magazine (October 1994). Shockingly, the article contains no cautions against the use of clumping litters, even though the description of one of the main ingredients in such products should be enough to alarm any thinking person.

“Sodium bentonite, a naturally swelling clay, is often added as an extremely effective clumping agent. When liquid is added, bentonite swells to approximately 15 times its original volume. But because sodium bentonite acts as an expandable cement would, litters containing sodium bentonite should never be flushed; when they expand they can block plumbing.”

A few moments’ thought is all that is needed to realize that something able to block household plumbing must be wreaking havoc on the plumbing of our feline companions.

What about my kittens after I switched to a plant-based litter? Sadly, the two females died. Both were passing clay stools right up until the time of their deaths; one kitten was still passing clay almost two weeks after I switched litters. The two males survived, though it took months for them to fully recover. Only after switching to a completely organic, homemade diet was I able to clear up the last traces of their ordeal. And still I grieve for the kittens who died so needlessly.


You may feel as horrified as I do at the thought that there must be thousands of kittens and cats (and other animals) ailing or even dying from clumping clay litters. What can we do to prevent such suffering?

One thing is let the manufacturers know we won’t buy such products. My husband called a company that makes one of these clumping litters. The woman he spoke with said that the company is aware that clumping litters may be causing health problems, but that it is the consumer’s responsibility to make sure their cats don’t eat the stuff.

My husband pointed out that cats clean themselves with their mouths, so of course they’re going to eat the litter every time they use their cat boxes. Unfortunately, the company’s representative maintained her “buyer beware” position.

Given the attitudes of such companies, we can vote with our pocketbooks by purchasing products from businesses that are more responsive to our concerns. Be sure to let the makers of the clumping litter know why you no longer purchase their product. You might even choose to boycott all products made by these companies (it isn’t hard to find out who makes what—just read the labels). An even more effective move might be to show this article to the owners or managers of stores selling these products.

If you suspect that an animal may be suffering an ailment caused by clumping litter, take him or her to a veterinarian or holistic practitioner immediately, and explain what you think may be happening. If you encounter resistance, it may mean that the veterinarian is unfamiliar with the problem and doesn’t know how to handle it. Try to find a holistic vet—either locally or someone you can work with by phone—who has some experience with clumping litter impacting the intestines. Most importantly, replace the clumping litter right away with one of the plant-based alternatives. Even if your cat is healthy, it makes sense to switch to a different litter.

If you love cats as I do, spread the word. Tell everyone you know about this problem. Tell your veterinarian. You may save the lives of many kittens, cats, and other beloved creatures.

Is Clumping Cat Litter Safe?

Clumping cat litter is popular because of its convenience and effectiveness. But there has been a lot of controversy around clumping cat litters made with sodium bentonite clay, as anecdotal evidence has arisen to suggest that it may be dangerous to cats. Concerned owners fear that sodium bentonite clay, if ingested, could cause gastrointestinal blockage and even death. Here’s what you should know about clumping cat litter.

How Clumping Litter Works

Clumping cat litter is made with sodium bentonite, a natural clay that expands by fifteen times its size when it comes in contact with moisture. Sodium bentonite is also used in grout and other industrial sealants, and if you flush it down the toilet, it will clog your pipes.

Sodium bentonite’s absorbent properties make it a convenient choice for filling cat boxes. Clumping cat litter lasts longer, and offers a high level of odor control because waste can be removed almost immediately, keeping the box cleaner than traditional non-clumping litters.

Possible Dangers of Clumping Cat Litter

However, many owners are concerned that ingestion of clumping clay litter might harm cats. Kittens are especially vulnerable because their youthful curiosity makes them prone to taste cat litter. A small amount of sodium bentonite clay can cause severe GI blockage in a young kitten.

Older cats may also sometimes eat litter, especially if suffering from an idiopathic condition known as pica. Pica makes cats want to eat things that aren’t edible, including cat litter, wool and plastic.

Even if your cat doesn’t suffer from pica, sodium bentonite dust could settle on his fur. If he licks off this dust, some owners fear, a cumulative affect could result in health problems later in life. Clumping cat litter also contains quartz silica, which can cause respiratory disorders.

Manufacturers, as well as many owners, consider clumping cat litter to be perfectly safe. No scientific studies have been done about the dangerous of sodium bentonite in cat litter. Evidence of the dangers of clumping cat litter remains anecdotal, and therefore hard to prove.

Alternatives to Clumping Clay Litter

If you’re uncomfortable with allowing your cat to use a possibly dangerous litter, you can switch to one of the many natural and biodegradable options available today. Brands such as Feline Pine, Yesterday’s News and Swheat Scoop are made with biodegradable ingredients such as wood, paper and wheat. They are clay-free, chemical-free and completely safe for your entire household.

Training your cat to use one of these litters might be a little difficult, as some cats may be uncomfortable with the different texture and smell of a natural litter. Natural litters offer varying degrees of convenience and odor control; pine is a natural deodorant, and wheat based litters often clump as well as clay based ones. Experiment a little to find something that works for you.

Irritable Bowel Syndrome in Cats & Clumping Litter

It would seem the only connection between kitty litter and irritable bowel syndrome would be what Puss deposits in the litter box. An article in the mid-1990s triggered an avalanche of discussion over the potential dangers of clumping kitty litter, but currently no scientific evidence confirms clumping litter promotes IBS.

Birth of a Controversy

After years of relying on traditional litter, cat enthusiasts embraced clumping litter in the late 1980s. Clumping litter changed the way litter boxes were maintained. Old-style clay litter was shoveled out of the pan to get as much pee and poo left behind by Puss after she did her business. Clumping litter made the job easier and cleaner because urine formed into a solid mass, easily scooped out with the other solids. All was well until 1995, when the now defunct magazine “Tiger Tribe” published an article questioning the safety of clumping litter, particularly for kittens. The author of the article, a breeder, experienced the death of three litters of kittens who suffered vomiting, diarrhea, and nasal and eye discharge soon after they began using the litter box. Since publication of the article, cat owners around the world have taken to the Internet to ask about, and warn of, potential dangers of clumping clay litter and the potential link to irritable bowel syndrome and other ailments.


Irritable bowel syndrome, or IBS, is not linked with gastrointestinal disease; it’s usually associated with chronic inflammation of the cat’s bowels. It can be difficult to pinpoint the cause, but allergies, diet intolerance and the inability to pass food through the gastrointestinal tract are suspected causes. Symptoms include chronic diarrhea, passage of small amounts of poop and mucus, constipation, nausea, abdominal pain, bloating and vomiting.

Ingesting Kitty Litter

If you’ve watched Puss groom, you know cats practice good hygiene; their paws are instrumental in the grooming process. Anything that ends up on your cat’s paw most likely will end up in her mouth and eventually her belly. You’ve probably had to sweep up litter Puss has sprinkled in a path from her toilet, so you know litter clings to her paws. It’s easy to see how she can easily ingest stray bits of litter from her paws as she grooms herself, a common concern with clumping litter. It’s understandable to question whether ingesting litter could affect her digestive tract.

Sodium Bentonite

Sodium bentonite is a natural substance traditionally used as a sealant, also widely used as a clumping agent in kitty litter. While it doesn’t contain anything toxic, it’s potentially troublesome because it swells up to 18 times its dry size when it gets wet. When Puss grooms herself and ingests stray grains of litter, the litter may swell inside her; it can cause problems if she ingests enough. There’s nothing beyond anecdotal evidence linking sodium bentonite in clumping litter to IBS, and according to the ASPCA, small amounts of such litter should pass through a cat’s digestive tract without issue.

Kittens and Clumping Litter

The ASPCA notes it may be beneficial to delay introducing kittens to clumping litter until they’re 3 or 4 months old. Little kittens aren’t steady on their feet and sometimes take a fall into the box, ending up with a mouthful of litter. Some kittens enjoy playing in their litter box, even eating the stuff. Waiting til Puss is a bit more mature helps ensure she won’t ingest large amounts of litter that may upset her belly from any silica or sodium bentonite in the litter.

Other Clumping Litter

If you’re concerned about Puss potentially ingesting sodium bentonite or you don’t want to wait to transition your kitten to clumping litter, there are options beyond clay-based clumping litter. Corn and wheat are two natural, biodegradable alternatives that clump for easy cleaning. As well, if Puss ends up eating a few of the grains, they’ll pass through her digestive system with no problem.

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