Cats can be prone to urinary tract issues like infections and the formation of stones which can lead to pain and life-threatening urinary blockages, particularly in male cats.

You may have seen ads for health monitoring cat litter than can alert owners to urinary health problems in their cats. How does this work? An article in Chemical & Engineering News explains the science behind this new kind of litter.

Most health monitoring litters are made from silica, rather than clay or other materials. These silica crystals start out colorless but are designed to change color based on the pH levels in your cat’s urine. PH measures how acidic or alkaline a substance is. The litter can also indicate the presence of blood in the urine.

The colorimetric information is:

• Orange: Acidic
• Yellow to Green: Normal
• Blue: Alkaline
• Red: Blood

The normal pH level for cats is between 6.0-6.5. Abnormal pH (either too acidic or too alkaline) can be an indicator of health issues like bladder stones or infection. Blood in the urine can also be a sign of health problems.

If you use health monitoring litter, keep an eye on litter color as well as your cat’s litter box behavior. Litter box problems like frequent trips to the box, excessive licking, low urine production, or signs of pain and distress could indicate an infection or a urinary blockage.

See your vet as soon as possible if you see these behaviors–no matter what type of litter you use–as a urinary blockage can be a life-threatening emergency.