Most cat litter products are made out of organic materials such as bentonite clay or silica. These substances are considered to be chemically and biologically inert, and they do not pose a toxic concern for pets.
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 ingests a large amount of litter (as can happen when a dog "cleans out" the litter box), gastrointestinal upset, constipation, and in rare cases, intestinal obstruction could occur.
It is generally recommended to avoid the clumping-type litters for kittens under 4 months of age; the fine particles can cause intestinal obstruction if consumed by young kittens.
This information was provided by the ASPCA Animal Poison Control Center and can be accessed at www.aspca.org.
