Why Does My Cat Smell Like Rotten Eggs?

why does my cat smell like rotten eggs

Imagine enjoying a glass of wine or coffee on the couch when suddenly, an unmistakable stench fills the air.

The first thought would be a truck full of rotten eggs just drove by your house. You glance over to find your cat looking innocently back at you.

You have now sighted the smelly culprit but something doesn’t quite seem right.

Why does my cat smell so bad?

A bad smell coming from a cat could be due to an underlying health issue. This can be caused by infected anal glands, dental disease or digestive issues.

In this article, we’ll dive nose-first to unravel this pungent enigma and how you can get rid of it.

Why Does My Cat Smell So Bad?

Most cat owners will agree with me that cats do smell good in general. I love smelling my cat, too much actually.

There’s even a company in Japan that sells a spray that smells like the top of a cat’s head.

But there have been times when I smell a foul odor coming from my cat. And when that happens, it could be due to the following reasons.

Toilet Misadventures

“When this happens, your cat will smell like a dirty litter box on wheels.”

The presence of bodily waste on your cat can leave it smelling like a tray of rotten eggs.

Cats are notorious for their impeccable grooming habits, but accidents do happen from time to time.

If your cat is having diarrhea or got into a litter box mishap, its fur or paws can be tainted with fecal matter.

When this happens, your cat will smell like a dirty litter box on wheels.

A cat that has bowel issues will start to meow when using the litter box. That is a good enough sign to check on your cat.

How Can I Get Rid Of The Smell?

The moment the smell hits your nose, immediately inspect your cat’s rear end for any signs of poop.

Cleaning your cat with a damp cloth or pet wet wipes will resolve the issue.

But if that doesn’t work, I would strongly suggest giving your cat a warm shower to clean it up.

For long-haired cats, make sure that the fur around your cat’s butt is well-trimmed to prevent staining mishaps.

Scooping out soiled cat litter at least once a day will help prevent your cat from stepping on its own waste whenever it uses the litter box.

Impacted Anal Glands

cat back view

Another reason that could have your cat smelling like rotten eggs is the anal glands.

Every cat has a pair of anal glands that are situated just at the entrance of its anus.

Your cat’s anal glands contain a dark oily fluid that is used for marking territory and lubricating its stools.

It has a deep pungent odor, almost fishy in nature.

When your cat doesn’t empty its anal glands regularly, they can become impacted or infected.

It can cause discomfort to your cat and give off a foul smell. Your cat can also start to leave tiny blood spots behind because of this infection.

Here are the common signs of anal gland problems:

  • Excessive licking or biting at the rear end
  • Scooting or dragging their rear across the floor
  • Swelling or redness around the anus
  • Difficulty or discomfort during defecation
  • A strong, unpleasant odor

Treatment For Impacted Anal Glands

The only way to resolve your cat’s anal gland issues and get rid of the smell is a visit to the vet.

The quickest way to relieve the anal glands is to manually express it.

The vet will do it once at the clinic and you will have to carry on the process at home until your cat is fine.

Antibiotics will also be prescribed to help clear up any infection.

Skin And Coat Infections

A skin infection does not seem like a big issue but can cause a bad odor if allowed to fester without treatment.

I know this firsthand when I was volunteering at my local pet shelter.

They had separate enclosures for cats with skin issues and some of them smelt really bad.

Bacterial Or Fungal Infections

There are millions of bacteria and fungi that are living on your cat’s skin.

On a good day, they don’t cause any issues and can live in harmony with your cat.

But if these microorganisms start to develop in large numbers, it can lead to a skin infection in your cat.


Similar to humans, your cat can be allergic to things that you might not be aware of.

The most common triggers are dust, pollen and even certain food items.

A study suggests that the balance of bacteria on a cat’s skin plays a role in its overall skin health.

A study has shown that an imbalance in these bacterial communities might contribute to the development of skin allergies in cats.

Many cats are known to be allergic to dairy products and nuts. So refrain from feeding milk and nut-related food products to your cat.

The most common sign of an allergic reaction in your cat is itchy skin around its face area. Your cat can also be sneezing and coughing.

Poor Grooming Habits

When it comes to personal grooming, there’s no other animal that does it as well as cats.

A cat can easily spend up to 5 hours a day grooming itself.

Grooming is actually important for cats as it helps to get rid of dust and loose fur on its coat.

This is why cats are known to frequently hack up a hairball from swallowing all that fur.

There are some natural remedies for hairballs that you can try if your cat has it on a regular basis.

Matting is a common problem in long-haired due to poor or inadequate grooming.

Tangled fur can obstruct normal airflow to the skin, create open wounds and tears and produce a foul odor.

Treatment For Skin Issues

When your cat has skin problems, the most common thing that it will be doing is scratching, licking and biting the affected areas. 

This can cause its skin to tear, bleed and get badly infected. 

It won’t be long before your cat’s skin will start to emit a very bad smell due to the infection. 

You will need to get your cat to the vet to get sorted out. 

Antibiotics, anti-inflammatory meds and medicated shampoo can help your cat with the skin infection. 

For allergies, antihistamines will be required if the symptoms are bad and make sure to keep your cat away from the allergens. 

If you have a long-haired cat like a Maine Coon, you need to be on point with its grooming to prevent matting. 

Make it a point to brush your cat every day and sent it to the groomer more regularly. 

Dental Diseases

“Bad breath in your cat is a clear sign that something isn’t right with your cat’s dental health.”

I refer to dental diseases in cats as the ‘Kiss Of Death’ because that was what my cat’s mouth smelt like when he had dental problems. 

My cat has FeLV and despite my best efforts to keep his oral health on point, his gingivitis just wouldn’t let up. 

In the end, the vet had to extract the majority of his teeth to prevent further damage. 

Up to 90% of cats that are four years or older suffer from some form of dental disease. 

This can be caused by an underlying medical condition or lack of oral care. 

The most common form of dental diseases in cats are:

  • Gingivitis
  • Periodontitis
  • Tooth decay

Most dental diseases start off with the build-up of plaque, a sticky film of bacteria, on the teeth which then hardens to form tartar. 

Over time, this bacteria will start to infect and erode the gums and make its way to the root of the teeth. 

When this happens, it can lead to tooth decay and abscesses.

Bad breath in your cat is a clear sign that something isn’t right with your cat’s dental health. 

Treatment For Dental Diseases

cat with no teeth

Prevention is always better than cure. 

Start brushing your cat’s teeth as soon as you get your cat. 

It is never too late to start and it will save you and your cat a lot of stress and anxiety over the long run. 

As a cat owner myself, I understand how difficult it can be to brush a cat’s teeth but it can be done with patience and effort. 

If your cat’s breath makes you gag or you notice swelling in your cat’s gums, a visit to the vet is needed. 

Your cat will have to undergo a dental procedure to get its teeth cleaned. 

Flatulence And Digestive Issues

Many cat owners are rather taken aback when I tell them that cats fart. 

Your cat’s fart might not be as loud and stinky as a dog’s but it passes gas quietly and without much smell. 

But when your cat’s farts smell like fermented rotten eggs, flatulence and digestive issues could be the culprits lurking behind the scenes.

There are some factors that can mess up your cat’s stomach. 

The Role Of Diet

What type of diet is your cat currently on?

Are you making sure that your cat’s diet is fulfilling its nutritional requirements?

Cats are obligate carnivores which means that they need to consume animal protein to survive. 

These days, many cats are fed dry food or kibbles which contain a high level of grain and carbohydrates.

Here lies the problem. 

Your cat isn’t able to digest and break down carbs. 

If your cat is currently on a high-carb diet, a lot of the carbs will just get stuck in your cat’s digestive system and intestinal tract. 

They will start to ferment and produce excessive gas which will then exit your cat’s behind as rotten egg farts. 

Gastrointestinal Disorders

It is possible for your cat to still have stomach issues even when it’s on a good diet. 

This can be caused by:

  • Intestinal parasites
  • Inflammatory bowel disease (IBD)
  • Poor gut flora

Cats with the above problems will have symptoms such as diarrhea, lack of appetite, vomiting, and signs of parasites in their fecal matter. 

Treatment For Digestive Issues

If your cat’s diet is mainly dry food and kibbles, it is time to make a change to wet food or a raw meat diet. 

This will ensure that you are feeding your cat food that it can break down and use as energy. 

If your cat is showing signs of digestive trouble even on a good diet, you need to take your cat to the vet for a check-up. 

There’s a chance that your cat might have IBD or intestinal worms which require medication to resolve. 

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