foul smelling cat urine
Questions About Cats

Why Does My Cat’s Urine Smell Strongly of Ammonia?

Cat urine has a strong, distinct scent. This is due to urea, which is the primary component of cat urine. Left uncleaned, urea decomposes and undergoes a series of chemical reactions. Chief among these is the release of ammonia into the atmosphere.

Even the smallest amount of ammonia creates a distinct, unpleasant smell. The odor is stronger in unfixed male cats. Dehydration, bladder stones, urinary tract infections, kidney problems, and food sensitivities can also lead to strong-smelling feline urine.

Do not ignore a strong smell of ammonia in your cat’s urine. The strong smell will encourage your cat to continue eliminating in the same spot. If this is outside the litter box, it can quickly become problematic.

Why Does Cat Pee Smell Like Ammonia?

The scent of feline urine is an unappealing discovery for new cat owners. Cat urine is made up of a number of different elements. These include:

  • Urea
  • Creatine
  • Uric acid
  • Sodium chloride
  • Electrolytes

When a cat urinates, the body is purged of urea. Urea then stagnates and decomposes. When this happens, the urea starts to release all the components that it is made of. This includes ammonia, which is a compound with an unmistakable odor.

Fresh cat urine is no stronger than the scent of other animal pee. If you clean your cat’s litter tray regularly, you should not notice the smell. If your cat’s pee smells strongly of ammonia all the time, there will be a medical explanation.

Do not settle for changing your cat’s brand of litter. Masking scents also doesn’t change the fact that a cat’s pee should not smell so strongly. 

Intact Male Cats

Tomcats that are yet to be neutered are more territorial. These cats will often urinate outside the litter box to claim territory. This can go unnoticed, allowing the urea to break down and release more ammonia.

This may be offensive to a human nose, but it will attract the cat. He will acknowledge the scent and continue to eliminate in the same spot. This can lead to great difficulty in litter training. A stubborn cat will consider himself entitled to use marked territory as he pleases.

Unfixed males already have stronger-smelling urine as a matter of course. Urine is not just a bodily function to cats. It is also a form of communication. This can be important to cats looking to mate. Females use pee to issue a come-and-get-me plea. Males urinate to announce that they plan to mate with intact females in the area.

When a male cat is neutered, he automatically undergoes a range of hormonal changes. As well as significant drops in testosterone, a neutered male has less urea in its urine. The urea found in urine is measured in molar mass per liter (mmol/l.) For comparison:

Human535 mmol/l
Female Cat940 mmol/l
Neutered Male Cat902 mmol/l
Intact Male Cat1,640 mmol/l

The levels of urea in female cats remain largely unchanged by spaying. There is a drastic drop in the level of urea when a male is neutered, though. Coupled with the fact that fixed males are easier to litter train, this makes neutering advisable.


Dehydration is the most common explanation for strong-smelling urine in cats. When a cat drinks water, it dilutes the elements of urine. If your cat is not drinking enough, its urine will be increasingly thick. This will release more and more aromas.

Dehydration is a common complaint in cats. Sometimes, it caused by excessive ambient temperatures. Your cat may be reluctant to drink water for medical reasons, such as dental pain. More likely, your cat simply isn’t compelled to drink water.

Cats are descended from desert-dwelling ancestors. This means that many cats live on the brink of dehydration near-constantly. In addition, cats are fussy about drinking water. Many cats will reject water in a bowl for a number of reasons. These include:

  • The smell of chlorine or other cleaning agents
  • Bowl is too deep, causing whisker fatigue
  • Too much or too little water in the bowl
  • Bowl is too close to food or litter tray, tainting the taste

Some cats also have an instinctive distrust of still water. These felines prefer to drink from a running source of water. Get your cat hydrated to rectify the issue of ammonia-smelling urine.

how to neutralize ammonia in cat litter

Encouraging a Cat to Hydrate

Get to the bottom of why your cat is not drinking enough water. Start by moving your cat’s water bowl. This should never be located next to food or a litter tray. Try changing the bowl, too. Ensure it is wide enough that your cat’s whiskers do not touch the sides.

Work on the scent of the water. Use a water purifier when offering tap water. This will remove the natural smell of chlorine. If this does not help, try bottled water. You could also drizzle something tempting, such as tuna juice, into the water.

If this still does not help, run a tap. If your cat approaches and starts to drink, your cat dislikes still water. Invest in a water fountain from a pet store. Most cats will gladly drink from such a resource.

You can also hydrate your cat through food. If your cat subsides on kibble, pour gravy or bone broth on the food. This will provide much-needed liquid. You could also freeze these meaty liquids into ice cubes. Offer these are treats during the summer months.

Once your cat is appropriately hydrated, this may resolve the strong scent of its urine. If not, there is a further medical problem to diagnose.

Excessive Protein in the Diet

An inappropriate diet can be to blame for strong-smelling cat urine. The Journal of Nutrition explains that cat urine should maintain a pH between 6.0 and 6.4. Urine with this level of acidity will have a comparatively inoffensive scent, similar to human pee.

Excessive or inappropriate protein in a cat’s diet can cause higher concentrations of acid in urine. When your cat consumes protein, the body turns the proteins into amino acids. What is left is turned into ammonia, which is then converted to urea by the liver.

If your cat is eating too much protein, the liver struggles to keep up. This is especially common in senior cats. As cats age, their organs age with them. The liver may not be as effective as it once was. While protein is important, your cat can have too much of a good thing.

Feed your cat an age-appropriate diet. Any reputable brand will have a range of foods, especially for senior cats. The nutritional composition of this food will factor in reduced liver performance.

You can also consider switching your cat to a different protein source. If your cat currently derives protein from meat, try fish – or vice versa. Just manage the transition gradually. You may find a different protein source manages the balance of ammonia in your cat’s urine.

Urinary Tract Infections (UTI)

Urinary tract infections can effect cats, especially females of middle age and beyond. According to the Journal of Veterinary Internal Medicine, diabetic cats are also at enhanced risk. Strong, ammonia-scented urine is a key symptom of feline UTIs.

Urinary tract infections are caused by bacteria inside a cat’s bladder. Cystitis is the most common diagnosis. Most often, UTIs are caused by stones in a cat’s bladder.

Bladder stones are caused when minerals in a cat’s urine are not processed appropriately. These minerals, called uroliths, form small crystals. Over time, these crystals will harden and grow in size. They will then form stones that block urine flow.

Aside from foul-smelling urine, symptoms of bladder stones and UTIs in cats include:

  • Difficulty urinating
  • Crying out when urinating
  • Urinating outside the litter box
  • Blood in the urine
  • Excessive grooming of the urinary opening
  • Reluctance to leave the litter tray

Always have a cat with a UTI examined. Some cats will conquer the problem naturally. Your cat will be in significant pain until this happens, though. In addition, UTIs can spread and cause secondary health concerns. A short dose of antibiotics will usually resolve the issue.

litter box smells like ammonia

Acute Uremia (Kidney Issues)

As cats grow older, the risk of renal failure becomes ever more prominent. Kidney problems can be hard to detect in cats. A cat only needs around 25% of kidney efficiency to thrive. A scent of ammonia in the urine can be a warning sign, though.

Injury or deterioration of kidney performance can lead to a condition called acute uremia. Acute uremia arises when the kidney cannot process waste and send it to the bladder. This leads to a build-up of urea – and ammonia – in the cat’s body. Aside from strong-smelling urine, symptoms of acute uremia include:

  • Ammonia-smelling breath
  • Ulcers in and around the mouth
  • Vomiting and diarrhea
  • Fever
  • Decreased urine output
  • Fever (body temperature above 103 degrees Fahrenheit)
  • Abnormal heart rate

Acute uremia can be treated if captured early. Acute kidney failure can be reversed. Dialysis of the kidneys will usually be required. Injury or toxicity are the likeliest causes of this concern.

Unfortunately, acute uremia can also be a symptom of Stage III kidney failure. According to the Journal of Feline Medicine and Surgery, renal disease is among the most common health ailments faced by senior cats.

If this is the case, you’ll need to make some tough choices. Kidney failure will eventually be fatal for your cat. With appropriate treatment and medication, though, you can extend your cat’s life. Cats have been known to live five years or more with stage III kidney failure.

At the first sign of acute uremia, seek advice. Where kidney issues are concerned, there is no time to waste. It’s possible that your cat will make a full recovery if caught early enough. Even if this is not the case, you can make your cat more comfortable.

All cat urine is capable of smelling of ammonia. This is especially likely if the elimination happens outside the litter box. Cat urine can stain and will start to smell increasingly strong. Fresh cat pee should not smell so offensive, though.