Why Is My Cat Eating Litter?

By Katie Grzyb, DVM on May 15, 2023

Cats are curious creatures and can sometimes develop odd inclinations to what they eat based on texture and taste. This can lead to ingestion of interesting items that we humans would not consider edible, such as cat litter. The repeated abnormal ingestion of substances not normally eaten is a health condition known as pica.

With pica, it is important to investigate whether there is an underlying medical issue causing the behavior. Acute (sudden onset) pica usually has a medical condition causing it, and chronic pica might be related to medical issues or secondary to self-soothing or obsessive-compulsive behavior. A thorough history, physical examination, and diagnostic testing can help investigate this peculiar activity.

Why Do Some Cats Eat Litter?

Aside from pica, there are many other underlying reasons that a cat may ingest cat litter, including:

Curiosity: Many kittens will play with cat litter just as they play with toys. They can even ingest the litter during play, which can become a problem if it becomes impacted in their gastrointestinal tract.
Food scent: Litter made from food-based products such as corn cobs or husks, walnut shells, wheat, or grass can be enticing to cats because of their scent.
Anemia: In this condition, there are too few red blood cells in the body. Red blood cells act as oxygen transporters to other body cells performing daily functions. Without these oxygen-carrying red blood cells, cats become tired and less playful, and may have pale gums.
- Anemia can be caused by many underlying medical issues, including toxins (such as lilies, Tylenol®, zinc, copper), kidney failure, immune-mediated disease of the bone marrow, viruses such as feline leukemia (FeLV) and feline immunodeficiency virus (FIV), blood-borne parasites (such as mycoplasma), severe flea infestation, and/or certain types of cancers.
Dietary deficiencies: Cats need certain nutrients in their diet to grow and thrive. Feeding only dog or human food to a cat or adult cat food to a kitten can lead to your cat searching out other things to fill their stomach—including cat litter. It is important to have your cat on a life-stage appropriate, well-balanced cat food to support their health.
Intestinal parasites: Worms and other parasites, such as coccidia and giardia, have led to pica in cats. While the connection isn’t clear, this is believed to be related to a persistent state of hunger and the idea of dislodging worms from the cat’s gastrointestinal tract.
Hyperthyroidism: Rarely, this medical condition can lead to pica due to the high levels of thyroid hormone, which can cause an increased metabolism and excessive appetite.
Brain tumors: Dependent on the location of the tumor, masses can cause pressure on certain areas of the brain, which can lead to increased hunger and thus the eating of foreign material.
Boredom/stress: When cats become bored or have anxiety, they can react by ingesting cat litter. Keeping stress to a minimum and keeping your cat entertained with safe toys and playtime can help eliminate this behavior.
Coprophagia: Defined as eating feces, this is a common behavior seen in younger cats. This is usually secondary to curiosity but can also be due any of the medical issues listed above, most commonly intestinal parasites. Appropriate diagnosis and treatment can help lessen this behavior.

Is Litter Toxic to Cats?

Cats are selective about where they go to the bathroom and what material they eliminate on. While there are several different materials commonly used for cat litter, most cat litter is designed for human appeal and does not take cat preferences into consideration. A study found that clumping litter containing activated charcoal is preferred by cats over other scented litters.

Each of the common types of cat litter has its pros and cons. Some cat litter is toxic, especially if ingested in large amounts or ingested chronically over long periods of time.

Signs of litter toxicity include nausea, lack of appetite, vomiting, diarrhea, lethargy, weakness, coughing, trouble breathing, or wheezing.

Clumping Clay Litter

Clumping clay litter has been linked to vomiting, diarrhea, gastrointestinal obstruction, and respiratory problems in cats. Ingestion of this litter can form a cement-like concretion of material in the stomach, leading to blockage of movement in the intestines. Surgical removal of this obstruction is sometimes necessary. Clay litter can also create a dust cloud when poured or scratched at. This dust can be inhaled or licked off the paws when cats clean themselves. The dust inhaled can coat the lungs and airways, leading to respiratory issues. Licking causes the dust to coat the gastrointestinal tract, leading to belly upset.

Crystal (Silica) Litter

Another recently popular type of litter, crystal litter, though labeled non-toxic, can also cause safety issues in cats. This type of litter is made of silica gel (silica dioxide and water). The clumping formulation of this type of litter runs the same risk of gastrointestinal issues as clay litter does, including blockage. Though most manufacturers state that the potential for inhalation of silica is low, there is still some risk, which can lead to respiratory issues.

Corn, Walnut, and Wheat Litters

Corn, walnut, and wheat are great biodegradable options for cat litter these days. Unfortunately, since they are naturally growing substances, they have a risk of fungus growth (specifically aflatoxin mold on corn), which can be extremely toxic—even fatal—to animals. Clinical signs of this toxicity include vomiting, diarrhea, lethargy, not eating, and jaundice. Walnut and wheat litter can also be quite dusty, leading to respiratory issues or belly upset if too much of the dust or product is ingested.

Paper and Wood Litters

Paper- and wood-based litter is growing in acceptance due to being biodegradable and environmentally friendly. These litter types are low in dust, scent-free, and highly absorbent. The litter is not considered toxic if ingested; however, if ingested in large amounts, it can still cause belly upset or blockage.

Wood and pine cat litter is also increasing in popularity due to being environmentally friendly, inherently scent-containing, and naturally anti-bacterial. However, some cats find this type of litter uncomfortable to walk on. Also, pine contains a chemical compound called phenol that is toxic to cats. Prior to going to market, this litter is heated and dried to eliminate most of the phenol, though small amounts remain. Ingestion of large amounts and/or chronic ingestion of phenol can lead to severe liver issues and even death.

What To Do if Your Cat Has Eaten Litter

It is important to monitor your cat to prevent litter ingestion, especially if your cat is young or has medical issues that can lead to pica, such as intestinal parasites or anemia. Most litter ingestion occurs in small amounts and will cause no side effects to your kitty.

If you notice that your cat is eating litter persistently, or if your cat stops eating, starts vomiting, starts having diarrhea, seems constipated, starts coughing or wheezing, or becomes lethargic, take them to the veterinarian for evaluation.

What Can Veterinarians Do for Cats That Have Eaten Litter?

Your veterinarian will take a detailed history of what your cat’s lifestyle, home environment, and clinical signs have been leading up to the veterinary visit. The vet will perform a thorough physical examination to assess hydration, heart rate, respiratory rate, lung sounds, and any belly pain.

Usually, bloodwork to assess for any systemic disease processes, a fecal test to assess for intestinal parasites, and abdominal imaging (most commonly with radiographs) to assess for any litter blockage within the gastrointestinal tract are performed.

It is rare for a veterinarian to induce vomiting in a cat that has ingested litter, as there are risks to blocking the esophagus (tube going from mouth to stomach), especially with clay litter, and often the procedure is not helpful.

Treatment may be as simple as outpatient therapy with anti-nausea and vomiting medications and fluid therapy. In more severe instances, hospitalization and even surgical removal of a blockage may be necessary. Appropriate treatment of any underlying disease process may also be necessary to eliminate the litter-eating behavior. This includes stimulating the cat’s environment if litter eating is considered secondary to compulsion or boredom.

How To Prevent Your Cat From Eating Litter

There are multiple ways to help prevent your cat from eating litter including:

Scooping the box at least once daily and cleaning litter that has fallen around the box
Cleaning out the entire litter box with soap and water every week, then replacing with fresh litter
Feeding your cat a well-balanced, high-quality commercial cat food to avoid vitamin and mineral deficiencies
Taking your cat for annual or biannual health examinations by your veterinarian, based on their age and health. These can help diagnose underlying medical conditions early and, even better, can help prevent some of these issues.
Stimulating your cat’s environment with safe toys and multiple levels in the home for your cat to play with
Keeping stress to a minimum
Monitoring your cat’s litter box practices closely. Consider changing the litter if you notice ingestion. It can be helpful to discuss these options with your veterinarian to help lessen this behavior.