Bad Breath and Drooling in Cats: What Your Cat's Mouth Is Telling You

In this guide

A cat's breath is never going to smell like flowers, but a sudden change, genuinely foul breath, or drooling in a cat that does not normally drool, is worth paying attention to. Both signs usually trace back to the mouth itself, though occasionally they point to something further down the digestive system.

The most common cause by far: dental disease

Periodontal disease, a build-up of plaque and tartar that inflames the gums and eventually damages the tooth roots, is extremely common in cats past middle age and is the single most frequent reason for both bad breath and drooling. As it progresses, eating becomes painful, which is why owners sometimes only notice something is wrong once their cat starts dropping food, chewing on one side, or eating less overall.

A second, distinctly feline dental problem worth knowing about is tooth resorption, where the tooth's own structure gradually breaks down starting at the root, often below the gumline where it cannot be seen. It affects a large proportion of cats at some point in their lives and is intensely painful, sometimes causing a visible jaw chatter or flinch when the affected tooth is touched, even before any bad smell develops. It can only be picked up reliably with dental X-rays, which is one reason a full anaesthetic dental check matters even when a cat's mouth looks reasonably clean on the surface.

Other causes worth knowing

• Stomatitis, a severe, painful inflammation of the mouth's soft tissue, more common in certain cats and sometimes linked to a viral infection
• Oral tumours, more likely in older cats with a persistent bad smell, bleeding, or a visible mass
• A foreign object stuck in the mouth or wrapped around the base of the tongue, such as a thread or a piece of bone
• Kidney disease, which can give the breath a distinctive ammonia-like smell, usually alongside increased thirst and urination
• Diabetes, occasionally giving breath a sweet, slightly fruity smell
• Nausea from an unrelated illness, which can cause drooling without any dental problem at all
• Exposure to a bitter-tasting or toxic substance, which typically causes sudden, dramatic drooling with no other explanation

What to do

A vet visit is the right next step for any persistent change in breath or unexplained drooling, since the cause ranges from something as manageable as a dental clean to something as serious as kidney disease. Expect an oral examination, possibly under light sedation if your cat's mouth is too painful to check while awake, and depending on findings, dental X-rays, bloodwork, or both.

Keeping a cat's mouth healthy

• Brush your cat's teeth a few times a week with a cat-specific enzymatic toothpaste, never human toothpaste, which can be toxic
• Offer dental treats or diets formulated to reduce tartar build-up, as a helpful addition rather than a replacement for brushing
• Book a veterinary dental check at least once a year, more often for senior cats
• Do not ignore a cat that has started chewing oddly or favouring one side of its mouth, since this is often the first visible clue something hurts

Article content © Ravi Teja. All rights reserved.