Why Does My Cat Smell Bad? Causes and When to See a Vet

The vet sources below link a bad smell on a cat to four places: the mouth, the back end, the skin (including an abscess that has burst), and the ears. Cats are very fastidious by nature, so a smell that stays is worth chasing down. Start by finding where the smell is strongest, then read the section for that spot.

The cause decides the treatment, and a vet exam is how you find the cause. That goes for every one of your feline friends.

Where The Smell Is Coming From

Bad Breath And Dental Disease

VCA Animal Hospitals says, “Dental disease is one of the most common medical conditions seen by veterinarians. More than half of all cats over the age of three have some form of dental disease.” Its list of signs includes pawing at the mouth, head shaking, and jaw chattering, and it adds, “Halitosis (bad breath) is also common.”

International Cat Care lists bad breath (halitosis) first among the signs of dental disease, ahead of red, sore, and bleeding gums, reduced appetite, weight loss, and mouth pain. The Merck Veterinary Manual says, “Bad breath and drooling are common with inflammation of the mouth or tongue.”

International Cat Care also says, “Cats will often hide signs of pain, so it’s also not uncommon for them to show no signs yet have severe dental disease.” It adds, “If your cat is showing any signs of dental disease, contact your veterinary team for an appointment.”

Tartar is the hard, cream, yellow, or brown deposit on the teeth. International Cat Care says, “Because it’s hard, it can’t be removed by brushing your cat’s teeth,” and a dental scale and polish done by the vet under anaesthetic is usually needed. VCA adds, “Do not try to remove tartar yourself with any form of metallic instrument.”

On preventing dental disease, VCA says, “The most effective way to reduce plaque and tartar is to brush your cat’s teeth daily.”

Stinky Rear End

VCA explains that a cat has two anal sacs, small pouches on either side of the anus, and that “The walls of the sacs are lined with many glands that produce a foul-smelling fluid.” The fluid is normally squeezed out when the cat passes a bowel movement, “providing a distinctive odor (or unique ‘scent signature’) to the feces.”

The trouble starts when the sacs get plugged. VCA says, “The secreted material in the anal sacs is an ideal medium for bacterial growth, allowing infections to form.” An abscess that bursts “will release greenish-yellow or bloody pus through an opening in the skin beside the anus.”

VCA lists the first signs as “scooting or dragging the anal area along the ground and licking or biting at the rectum or the tail.” It also says, “Anal sac disease is very painful, and even a normally gentle cat may scratch or bite if you attempt to look at the affected area.” VCA lists the treatment as expressing the sacs, antibiotics, pain relief, and, for an abscess that has not ruptured, surgery that “may be necessary to lance the abscess.”

VCA says repeat anal sac disease can happen “in cats with obesity, chronic diarrhea, chronic constipation, inflammatory bowel disease, allergies (including food allergies), and abnormal anatomy or neurologic function.”

Loose stools can soil the fur at the back end. VCA says, “In long-haired breeds, you may notice staining or soiling of the fur around the back end.” Its advice on loose stools is, “If frequent liquid or semi-liquid stools persist for more than two days, you should consult your veterinarian.”

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Weight, Grooming, And Skin

Overweight cats, VCA says, face “skin and coat problems” among the “potential complications of obesity in cats.” VCA’s page on seborrhea lists “Obesity or musculoskeletal disease or pain that make the cat unable to groom properly” among the medical problems behind secondary seborrhea.

VCA’s obesity page says the vet sets the plan: “work with your veterinarian and healthcare team to select an appropriate diet and adjust feedings for weight loss.” It names a specific portion and a specific meal frequency as part of that plan. Ask the vet about the diet, the portion, and the feeding schedule that fit your cat.

Check out the book The Natural Cat for detailed cat bathing advice. Talk to a groomer who is experienced with cats if you are uncomfortable trying it yourself at home.

Seborrhea is a skin disorder in which the skin makes too much sebum, an oily, waxy substance. VCA says, “Many cats have an odor that is associated with seborrhea. This odor is usually worse if the seborrhea is complicated by a secondary bacterial or yeast skin infection.” VCA also says, “Affected areas of skin often flake off like dandruff, which can be seen on the cat’s sleeping areas.” On treatment, it says, “Treatment is aimed at the underlying cause.”

Abscesses

VCA says an abscess is a “pocket of pus,” and “Some abscesses will rupture, discharging a foul-smelling thick liquid.” It says, “One of the most common causes is a bite from another animal,” and that “cats that fight or go outside are at higher risk.”

VCA says, “The key is to remove the pocket of pus, either surgically or by draining and flushing,” and that appropriate antibiotic therapy is “a critical component of the successful treatment of abscesses.”

Ear Infections

VCA says of ear infections in cats, “The ears often become red and inflamed and may develop a bad odor. A black, brown, or yellow discharge is commonly observed.” Many cats shake their heads and scratch their ears.

VCA answers the question about over-the-counter ear drops with, “No, your veterinarian must diagnose the exact cause of the problem to select appropriate treatment.” It also says, “Normally, cats are resistant to ear infections, so if your cat develops otitis externa, especially if it recurs, it is necessary to look for an underlying cause.”

Kidney Disease In Older Cats

Kidney and urinary problems can show up as a cat drinking and urinating more than usual. The Cornell Feline Health Center says, “Chronic kidney disease, or CKD, is one of the most prevalent diseases in older cats, affecting up to 40% of cats over the age of 10 and 80% of cats over the age of 15.”

Cornell says, “In the early stages of CKD, it is very common for cats to show no obvious clinical signs.” Later, “cats may begin to urinate greater volumes and drink more water to compensate,” and cats with CKD may “appear lethargic, unkempt, and lose weight.” Cornell adds that “it is very important for all senior cats to be regularly monitored for this disease.”

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Smelly Cat Odor FAQ

Why does my kitten’s breath smell?

International Cat Care says, “Cats around five months of age quite commonly develop juvenile gingivitis, and you may notice an obvious smell to your cat’s breath.” It says this “will usually take 4-6 weeks to settle down. However, check with your veterinary team if you notice any abnormalities.”

Can I use human toothpaste on my cat?

VCA says, “Never use human toothpaste. Human toothpastes are foaming products and contain ingredients such as fluoride that should not be swallowed. Use pet toothpaste that is non-foaming and safe to be swallowed.”

How often should a vet look at my cat’s teeth?

International Cat Care says, “Cats should ideally have their teeth examined by a vet at least once every 12 months, and cats that have had dental problems should be examined once every 3-6 months, depending on their condition.”

Do a cat’s anal sacs need emptying on a schedule?

VCA says, “Cats with recurring anal gland issues may benefit from having their glands expressed (emptied) on a routine basis by veterinary professionals.” It also says that if several episodes do not respond to treatment, “the anal sacs can be removed surgically.”

Sources

• VCA Animal Hospitals. "Dental Disease in Cats." vcahospitals.com.
• International Cat Care. "Dental disease in cats." icatcare.org.
• Merck Veterinary Manual. "Inflammatory and Ulcerative Diseases of the Mouth" (disorders of the mouth in cats). merckvetmanual.com.
• VCA Animal Hospitals. "Anal Sac Disease in Cats." vcahospitals.com.
• VCA Animal Hospitals. "Diarrhea in Cats." vcahospitals.com.
• VCA Animal Hospitals. "Obesity in Cats." vcahospitals.com.
• VCA Animal Hospitals. "Seborrhea in Cats." vcahospitals.com.
• VCA Animal Hospitals. "Abscesses in Cats." vcahospitals.com.
• VCA Animal Hospitals. "Ear Infections in Cats." vcahospitals.com.
• Cornell Feline Health Center. "Chronic Kidney Disease." vet.cornell.edu.