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Why Does Cat Urine Smell Like Ammonia? 8 Likely Reasons

Written by: Christian Adams

Last Updated on February 16, 2024 by Catster Editorial Team

cat owner collecting urine sample from her pet cat

Why Does Cat Urine Smell Like Ammonia? 8 Likely Reasons

One of the most common complaints about cats is the strong smell of their urine. Why does cat urine smell so bad? The answer has to do with chemistry. When cats pee, they can release compounds that form a highly pungent solution, or pee in ways that cause a build-up of those compounds in their environments.

There are many reasons why a cat’s urine might smell strongly of ammonia. Some cats may have underlying health conditions such as the presence of bacteria or fungus in their renal systems, alterations in the composition of their urine due to dehydration or hormone levels, and a lack of proper grooming or litter hygiene.

If the pungent smell of ammonia is annoying to you, it may be a sign that it’s time to take action for your kitty’s health. Read on to find out more about what might be going on with your pet’s pee.

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The 8 Reasons Why Cat Urine Smells Like Ammonia

1. Chemical Reaction

The ammonia smell in cat urine is often strong and unpleasant. The smell is caused by the presence of urea, a compound composed of carbon, nitrogen, and hydrogen that is produced when protein is broken down in your cat’s body. The ammonia smell is created when this urea decomposes and releases ammonia gas. The ammonia itself is not harmful to humans, but it can create an unpleasant smell and also cause staining.

This scent is particularly noticeable when cats urinate on carpets or other fabric surfaces. If a cat’s urine smells different than usual, it is important to take the cat to the veterinarian for evaluation.

woman collecting urine sample of an orange cat
Image Credit by: Yaya Photos, Shutterstock

2. Unfixed Male Cat

Unfixed male cats tend to mark their territory by spraying urine. This is done to let other cats know that this territory is occupied and to deter them from entering. This often results in them spraying urine in high-traffic areas of the home, such as doorways and hallways. While it is possible to train an unfixed male cat to stop using this marking behavior, it is not always successful and can be quite difficult.

The behavior is most common in unneutered males but can also occur in females who have not been spayed. With more cat pee spread around your home, it’s far more likely that the chemical process described above will have a chance to occur before you have a chance to clean up.

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3. Dehydration

When a cat is dehydrated, their urine will become more concentrated and will have a higher level of ammonia. This is because when the body is dehydrated, it tries to conserve water by increasing the ratio of urea to water in the urine. Along with making your pee smell more strongly of ammonia as it breaks down, dehydration is dangerous for your kitty. Dehydration can cause a change in the pH of urine, making it more acidic.

This can be irritating and toxic to the bladder and kidneys, leading to inflammation and even kidney failure.

4. Excessive Protein

A high protein diet in felines can lead to changes in their urine. The high protein increases the levels of urea because protein is broken down into amino acids in the body, and with higher acidity in urine, there will be more urea in the urine. This process is beneficial for cats because it can help to get rid of any excess toxins in their bodies. However, it will make your home smell bad!

In the long term, it may be worth looking at the balance of macronutrients in your cat’s diet and it is important to make sure that they also have plenty of water to drink so that they don’t become dehydrated.

cat eating boiled eggs
Image Credit by: Anastasiya Tsiasemnikava, Shutterstock

5. Urinary Tract Infections

Urinary tract infections (UTIs) are a relatively common problem in cats and can cause a variety of symptoms, including frequent urination, straining to urinate, blood in the urine, and even kidney failure. A UTI is usually caused by bacteria that travel up the urinary tract and infect the bladder or kidneys. The most commonly observable symptom in cats is frequent urination and urinating even when there is little urine in the bladder. This can lead to accidents around your home.

With a larger surface area exposed to cat pee, it’s more likely you’ll smell ammonia around the house. UTIs can be cured with antibiotics, and you must take your cat to the vet if you suspect this is the problem.

6. Kidney Problems

Kidney problems can change the smell of a cat’s urine. This is because when the kidneys are not working properly, they cannot filter out the toxins from the blood as they should. These toxins can cause the urine to smell different than normal. The odor may be stronger or more ammonia-like, and it can be difficult to get rid of. If your cat has a kidney problem, it is important to get them the help they need.

7. Older Cat

Renal problems are extremely common in older cats. This is because as cats age, their kidneys begin to fail and they lose their ability to properly process toxins, including urea. This may lead to changes in their urine odor which may smell more ammonia-like. In addition, the older a cat gets, the more difficult it becomes for them to groom themselves properly.

This can cause their fur to become dirty and they may not be able to clean pee off their hind legs and tail easily anymore. You can always take a wet wipe and clean your cat’s hindquarters and tail after they visit the litter box.

old calico cat
Image Credit by: Kristi Blokhin, Shutterstock

8. Injured Cat

Injured cats struggle to groom themselves and as a result, dirt and bacteria can build up on their fur. This can lead to urinary tract infections if the dirt or bacteria is transferred to their urethra. In this case, the ammonia smell is a sign that the cat is peeing accidentally in multiple places and the cat’s urinary tract is infected.

The other possibility is that, as with the older cat scenario above, you are smelling ammonia given off from the build-up of urea on the injured cat’s fur. In both scenarios, it’s important that you take responsibility for grooming your injured cat until they are well enough to do it for themselves. If you suspect a UTI you must take your cat to the vet immediately.

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In conclusion, the smell of ammonia from feline urea can be quite strong. This smell can be a nuisance to people and pets in the home. There are several things that can be done to reduce or eliminate this smell. Taking simple steps like scooping the litter box regularly and using good quality litter can help.

If the smell is still bothersome, using an air purifier may be necessary. Don’t forget that strong ammonia smells can be a sign of concentrated urea in your cat’s body or that they are spraying or having accidents around your home. Be sure to investigate any major changes in your cat’s urinary health, as the renal system is fragile in most cats.

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Featured Image Credit: Yaya Photos, Shutterstock

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