Causes of Bad Odors in Cats

Jennifer Coates, DVM
By Jennifer Coates, DVM on Jul. 12, 2017

By Jennifer Coates, DVM

When you think of smelly pets, cats aren’t the first species that come to mind. Cleanliness is one of their biggest draws, after all. So, if you start to detect a bad odor emanating from your cat, you need to take notice. In most cases, foul feline smells are a sign that something is seriously wrong.

The best way for pet parents to start to determine what could be making their cats smell bad is to focus on the exact nature of the odor and where on the body it’s coming from.

Mouth Odor

A healthy feline mouth doesn’t stink, but a lot can go wrong to change that. Dental disease is the most common cause of unpleasant cat odors. Plaque and tartar accumulating on the teeth, gums becoming inflamed and separating from their underlying structures, and loose teeth all provide the perfect environment for bad breath. Food lodges in abnormal gum pockets and rots there, and bacterial infections that produce foul odors can proliferate in the unhealthy environment. Bad smells may also develop as a result of foreign material getting lodged in the mouth, trauma to oral tissues, and oral tumors.

Sometimes systemic diseases will cause abnormal smelling breath. Most notably, kidney disease can lead to a urine or ammonia-like odor coming from the mouth. Diabetes mellitus may produce a sweet or “fruity” smell or, when a cat’s condition has worsened, an odor similar to nail polish. Cats with severe liver disease or an intestinal blockage may have breath that smells like feces.

Skin Odor

The skin is another relatively common source of bad odors in cats. Skin infections often develop as a result of other, underlying health problems such as wounds, allergies, parasites, cancer, immune disorders… basically anything that disrupts the skin’s normal protective mechanisms.

Bacterial infections usually have a putrid odor, but depending on the type of organism involved you may even notice a sweet smell. Yeast infections are typically described as smelling “musty.”

If your cat develops an abscess, oftentimes due to bite wound from another cat, and that abscess ruptures, you’ll probably notice a very foul odor associated with the pus as it drains.

Regular self-grooming is one of the reasons that cats tend to have little odor associated with their skin. When cats are sick or aren’t flexible because of arthritis or obesity, they can’t groom themselves well and may develop a greasy, unkempt coat that has a slightly “funky” odor.

Ear Odor

Most feline ear infections also have odors associated with them. Musty smelling yeast infections sometimes develop when a cat has an allergy or other condition that alters the environment within the ear in a way that promotes the growth of yeast.

Bacterial infections can have a no obvious underling cause or be related to allergies, polyps, tumors, foreign bodies, etc., and they tend to smell fetid or somewhat sweet, depending on the specific type of bacteria involved.

When cats have an ear mite infestation, their ears typically contain a dark material that looks a little bit like coffee grounds, which may have a foul odor associated with it. 

Rear End Odor

Healthy cats are such fastidious self-groomers that you rarely catch a whiff of urine or feces emanating from their back ends… unless they’ve just emerged from the cat litter box. But when cats can’t groom themselves normally, typically because of arthritis, obesity, or systemic illness, that might change.

Cats, particularly long-haired cats, with diarrhea can accumulate fecal material in the fur around their hind end, and a urinary tract infection might be to blame if you become aware of an unusually strong smell of urine from the rear end of your cat.

Cats have two anal glands, one on either side of the anus, that produce a musky or fishy smelling material. Under normal circumstances, pet parents are barely aware that these glands exist, but if your cat becomes scared or excited, he or she may release their contents. The smell can be truly overwhelming but as long as it only happens intermittently, it is usually normal.

Infections, tumors, and other conditions that affect the anal glands’ functioning can result in more persistent odors.

Getting Rid of Bad Smells in Cats

Of course, cats will sometimes smell for perfectly obvious and relatively commonplace reasons, like after eating a can of super stinky cat food or wandering outside and investigating the garbage, but unless you can easily identify a benign source of your cat’s odor, make an appointment with your veterinarian. The doctor will start with a complete health history and a physical examination (including a close look at your cat’s mouth, skin, ears, and hind end) and then should be able to tell you where the smell is coming from and what needs to be done next to diagnose and treat it.

Jennifer Coates, DVM


Jennifer Coates, DVM


Dr. Jennifer Coates is an accomplished veterinarian, writer, editor, and consultant with years of experience in the fields of veterinary...

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