Why does cat urine smell like ammonia?

Updated February 21, 2017

Cat urine can have a strong, distinct smell of ammonia. This is because cat urine is concentrated when expelled from the body and is ammonia-based. There are ways to reduce the ammonia smell. In some cases, a stronger urine smell could mean a sick cat, so if you find the smell has become increasingly odorous, consult your veterinarian.


Cat urine has a strong ammonia smell because cat urine is ammonia based. It is also concentrated and, when absorbed into a soft material like carpet, it can be difficult to remove. All cat urine smells like ammonia.

Possible Problems

A strong cat urine smell could also mean the cat has a bacterial infection or is not getting enough water. Be sure to have water available to your cat at all times. If you notice a sudden increase in the ammonia smell around your cat's litter box, you may want to take the cat to the vet to be sure a bacterial infection is not the cause.

Smell Prevention

It is possible to prevent the noticeable ammonia smell of your cat's urine. By using a clay-based or baking soda additive in your kitty litter box, you can reduce the smell after a cat urinates. It is important to regularly clean the litter box to be sure the smell does not build up. If you start to notice the ammonia smell drifting into other rooms of the house, it often means it is time to clean the litter box. Besides changing the litter, also completely wash the box once a month, to reduce staining and accumulation of ammonia-scented urine.

Other Causes

If you start to notice that your house repeatedly smells like cat urine, it could also be because the cat is urinating on the carpet. Carpet can hold the ammonia smell and make it more noticeable. Thoroughly clean the carpet. Urinating outside the litter box could also be another signal the cat is sick. If this is new behaviour, be sure to take the cat to the vet to check for other health issues.

Ammonia Cleaners

It is important to not use ammonia-based cleaners on cat urine. If you are cleaning the litter box or around the litter box with an ammonia-based cleaner, it will only increase the ammonia smell in your house. It is natural for cat urine to have a stronger smell than human urine because it is more concentrated. But, you do not want to increase the problem with your cleaning method.

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About the Author

Rachel Terry Swick graduated in 2004. Since then, Swick has worked as a reporter for both daily newspapers and weeklies. She currently works as a senior reporter for the Sussex Countian in Georgetown, Del. She holds a Bachelor of Arts in Speech Communication from Millersville University in Pa.