Stinky Breath: Why Does My Cat's Breath Stink and Is It Normal?

by K Marie Alto December 16, 2022 8 min read

Stinky Breath: Why Does My Cat's Breath Stink and Is It Normal?

There's a stereotype for most pets that they love to get up in our faces, but they have horrible breath. Cats are no exception to this, though they may not be as up-front about it as dogs.

The question is, is bad breath normal for cats, or is it a sign of something you should be concerned about?

Is Bad Breath Normal for Cats?

First, let's talk a bit about whether or not bad breath is normal.

A small amount of stank in your kitty's breath is normal. After all, they don't exactly brush, floss, and use mouthwash to keep their breath minty fresh. On top of that, the things they eat don't exactly smell pleasant themselves. If you've ever opened up a can of wet cat food – and I'm betting you have – you know that it's not really the most pleasant of smells. It's sort of like a dirty tuna or some meat that went a little off, right?

Cat With Bad Breath Image by Toe Beans

There's a level of bad breath that goes beyond just "what they ate," though, and that's where bad breath can get a little concerning for cats. Felines with bad breath might have another underlying condition going on.  

Causes for Bad Breath in Cats

If your cat has bad breath, like, worse than normal breath, it's worth thinking about the things that can cause it and giving your fur baby a once-over to see what you can find.

1. Bad Diet

First of all, a bad diet can cause bad breath. This happens a lot when you're feeding your fur baby the cheapest food you can get them to eat. No judgment here; sometimes we do what we have to when times are tough. But food that is full of additives and stuff your cat can't digest will have systemic effects.

A Cat Eating Image by Toe Beans

They'll have trouble digesting it, and some of the ingredients they can break down will decompose or digest into nasty bacteria and other chemicals that can cause stomach problems, organ problems, and, you guessed it, bad breath.

2. Fish Burps

A similar diet-related cause of bad breath is fish(in dogs, too). Cats love fish, and I mean lovefish. They're right to do so, too; fish is delicious. The trouble is, fish also digests in weird ways.

A Cat With Fish Image by Toe Beans

If you've ever taken a fish oil pill and had "fish burps," you know how that scent comes back up in a worse form than it went down. This happens just the same when your kitty is eating something fishy. So, if they have breath that smells like fish that was left out in the sun a little too long, this could be the cause.

3. Periodontal Disease

By far, the most common cause of bad breath in both people and in cats is periodontal disease. All that means is "tooth decay," and it's why we all visit the dentist for a cleaning every six months. Periodontal disease happens because of bacteria.

When you eat food, your mouth starts the digestion process. Chewing breaks down the food, saliva helps to start dissolving it, and the bacteria in your mouth add to the process. The same, of course, goes for cats, though they don't spend nearly as much time chewing as we do.

Vet Checking Cat For Periodontal Disease Image by Toe Beans

Mouth bacteria build up and stick to teeth, and over time, the chemicals they expel build up and harden. Unfortunately, this stuff smells pretty bad. Part of dental cleaning is scraping off this plaque before it hardens into tartar and becomes much harder to get rid of. Since your cat isn't brushing their little teefers every day, they suffer from a lot more of this build-up than we generally do.

Luckily, periodontal disease is also very easy to manage and care for, as long as your feline will tolerate a little tooth cleaning from time to time.

4. Gingivitis

Gingivitis is the swelling and inflammation of the gums. This can be caused by periodontal disease, particularly when it's left untreated. It can also be caused by everything from illness to mouth sores to injuries to the gums, like if your cat chomps on something a little too hard or sharp and scratches their gums.

It's also common in cases where something gets stuck in their teeth – whether it's a bit of kibble, a strand of cartilage from their food, or something inanimate stuck in there like a bit of plastic or string.

Vet Checking Cat For Gingivitis Image by Toe Beans

Whatever causes their gum issues, it leaves the gums sensitive and painful. They might not want to open their mouths because it hurts to do so. They also find it harder and more painful to eat dry food and might be more averse to it. When poked or prodded, their gums are also likely to bleed.

Gingivitis is generally not difficult to take care of, but depending on why it happens, the root cause might need to be addressed. If it's not something obvious, you may need your vet to help you diagnose it and find a solution.

5. Stomatitis

Stomatitis is sort of like an advanced form of periodontal disease or gingivitis, but it's not quite the same thing. For one thing, it's worse, and it's difficult to diagnose and deal with because of how it presents itself. 

Specifically, stomatitis is a swelling and inflammation of the mucous membranes and other areas around the mouth. Gums, tongue, cheeks, it all gets swollen and can rub into open sores. All of this is painful and irritating, and worse, vets aren't even sure what causes it in cats.

Vet Checking a Cat For Stomatitis Image by Toe Beans

Unlike gingivitis or periodontal disease, stomatitis is very hard to handle at home and will require treatment by your vet. In the meantime, your cat will have a hard time eating, grooming, and generally using their mouth for anything.  

There's also a related kind of stomatitis called Lymphocytic Plasmacytic Stomatitis. It's the same effect but with a different cause; vets believe it's related to feline leukemia, FIV, calicivirus, or bartonella. It's relatively rare but very extreme, so it needs treatment as fast as possible.  

6. Diabetes

While "bad breath" is kind of a generic descriptor, it can come in many different forms. While it might not be pleasant to you, giving that breath a second sniff can give you a few clues as to what might be causing it. Specifically, this and the next few entries on this list all have more characteristic smells.

Treating a Cat For Diabetes Image by Toe Beans

If their breath is bad, but it smells slightly sweet (or even verysweet), then it could be a sign of diabetes mellitus. This is an issue with the pancreas and is pretty similar to diabetes in people. It's just an issue with the body's ability to handle sugar, which can have pretty severe consequences if left untreated. You may want to change their diet to one that is diabetes-friendly.

7. Kidney Disease

Another issue that can be partially diagnosed through the breath is kidney disease. Kidney disease is, obviously, an issue with the kidneys and can be caused by a bunch of different things, from age to diet. The telltale here is an ammonia smell on the breath.

The kidneys are responsible for filtering gross waste from the blood and expelling it, primarily through urine; if they aren't working, the stuff that makes urine smell the way it does isn't expelled, so it builds up and can express itself through things like the breath.

Vet Checking a Cat For Kidney Disease Image by Toe Beans

Kidney disease can be very dangerous, so if you smell an ammonia-like bad breath on your fur baby's mouth, you should consult with your vet ASAP.

8. Liver Disease

Liver disease is another organ-related disease that you can usually smell on the breath.

Vet Testing Cat For Liver Disease Image by Toe Beans

Advanced liver disease can cause jaundice, which you'll see with a yellowing of the eyes, excessive thirst, a poor appetite, and other similar issues. It has a similar ammoniac smell to kidney disease since the two organs work together for the same purpose.

9. Other Issues

There are other possible causes of bad breath as well.

A Cat With Bad Breath Image by Toe Beans

These can include:

  • Oral cancers causing various bacterial and other problems in the mouth.
  • Localized infections in the mouth, usually because of a cut or scrape.
  • Rotting teeth, which is an advanced form of periodontal disease and requires dental surgery.
  • Gastric reflux, where the acid in the stomach works its way back up the throat, with all that entails.
  • Intestinal blockages, which can lead to the breath smelling a bit like feces.
  • Coprophagia – common in dogs, less so in cats – where the cat eats the feces, which can lead to that smell on the breath.

All of these are potentially dangerous causes. While not allbad breath is a sign of an impending crisis, many of them need to be addressed as soon as possible, so it's generally a good idea to have your vet on call when the breath starts turning bad.

How to Help Treat Bad Breath in Cats

While many of the causes of bad breath in cats aren't things you can handle at home, some of them are, and others are preventable.

Look At Your Cat's Diet

First and foremost, you want to look at your kitty's diet. The worse the food they're eating, particularly in terms of additives, the more likely they are to end up with issues because of it.

There's a lot of debate over what the best diet is, and some cats have particular preferences when it comes to food, but really a lot of it just comes down to feeding them healthy carnivore ingredients. The more fillers and non-carnivore foods you feed them, the worse off they're going to be. If you decide to change your cat's food, make sure you transition them to the new diet carefully

Brush Their Teeth

The other thing you can do at home is brush their teeth.

Brushing a Cat's Teeth Image by Toe Beans

Yes, that's right; a little kitty toothbrush and some toothpaste (or gel, rather) can go a long way.

Of course, your cat probably doesn't want you mucking about in their mouth, so you're going to have to train them to tolerate it. Starting young is the best option, so they can learn to tolerate it early, and you won't have troubles later in life. 

To train them, start by using a finger (with a protective barrier or not, depending on how bitey your fur baby is) and just gently pull back their lips and dab a bit of tooth gel on their teeth. You don't need to rub or jam your finger in their mouth, and you shouldn't try to pry their jaw open, either. Just get them used to the idea and experience.  

The key is to reward them after you do this with a high-value treat. Depending on the cat, this could be a bit of prized soft food, a drink from a running faucet, or another treat you know they love.  

Once they're more tolerant, you can start to use a brush instead of a finger. Similarly, as they grow more used to it, you can do a bit more aggressive brushing. Your goal is to get them to the point where they tolerate daily tooth brushing, even if it's cursory. Even a little bit is better than nothing.

When to Take Your Cat to the Vet

Your cat should have regular check-ups to evaluate their health, and those should include oral inspections. On top of that, you will want to take them to the vet if they have extremely bad breath, particularly if that foulness smells like ammonia or smells sweet. If it only lasts a day or two, don't worry about it. Otherwise, at the very least, you should call your vet and see what they have to say.

Vet Examining Cat's Oral Health Image by Toe Beans

Luckily, many issues that cause bad breath can be caught and treated early when you notice them and get the proper care. It's only when you accept bad breath as a fact of life and let the underlying cause fester that it can become a dangerous or even life-threatening issue. Do what you can to care for your fur baby's mouth, evaluate their diet, and make sure they get regular check-ups for the best possible chances of keeping them healthy.

Do you have any other questions about cat mouths or bad breath or anything else? If I didn't answer your question, let me know in the comments, and I'll do what I can to respond!

K Marie Alto
K Marie Alto

K. Marie is an animal lover, wife, kitty mom, dog auntie, writer, and co-founder of Toe Beans, a proud American family-owned online boutique pet supplies store focused on the improvement of the life of furry family members via pet parent education, better products, and advocacy. She has over 20 years of experience as a pet momma. She loves sharing her personal journey and experience as a pet parent via her blog and Facebook page where she currently has more than 30K followers (@furrytoebeans) and counting :-).

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