Cat litter is one of any of a number of materials used in litter boxes to absorb moisture from cat feces and urine, reducing foul odors such as ammonia and rendering them more tolerable within human dwellings.

Besides absorbancy and odor control, other factors to consider in litter choice are messiness (will the cat track the litter throughout the house?) and environmental factors (is it biodegradable?).

Conventional litter

One of the first commercially available cat litters was Kitty Litter, invented in 1947 and marketed by Ed Lowe . This was the first use of clay as an absorbent; prior to this time sand had been used in litter boxes.

Clumping litter

Clumping litters are made from clay, but are designed to clump together when wet and form a solid mass separate from the other litter. This solid clumped material can then be disposed of without changing the entire contents of the litter box often. It should be changed it on a regular basis to prevent buildup of bacteria, perhaps every four to six weeks. At the same time, the litter box itself should be disinfected.

Bentonite is often used to make clumping litters. Some claim that clumping litters can be harmful to pets because if it is ingested or inhaled, it swells and solidifies. For the same reason, it is not recommended to flush clumping litters down the toilet.

Alternative litter

Silica gel litter, a porous granular form of sodium silicate, has the highest absorbancy of any litter, and has excellent moisture and odor control. Other litter material is made of recycled paper, in the form of pellets.