What this means
A healthy cat's mouth hardly smells, unless it has just eaten fish or meat food. A sharp, rotten or unusually strong smell that does not fade after a meal and that you notice when stroking or when your cat yawns is a change worth noting. Gently lift the lip and look whether the gum edge is red and whether there is a brown or yellow layer on the teeth.
Tartar and inflamed gums are among the most frequent causes, but not the only one. Sometimes the smell points to a sore or loose tooth, a wound in the mouth or a more general illness, and certain smells, such as sweet fruit or ammonia, can come from somewhere else in the body. One cause cannot be told from the smell alone.
Cats hide a sore mouth. A cat may keep eating but chew carefully, leave the harder pieces, drool, groom less or rub its face. These everyday changes together with the smell deserve attention, and a cat that has not eaten for more than a day must be shown to a vet.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your cat.
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Plaque and tartar on the teeth
A film of bacteria on the teeth hardens into brown or yellow tartar, which gives off an unpleasant smell.
About the condition: Dental disease -
Inflamed gums
Red, swollen and tender gums let bacteria multiply. Eating may hurt.
About the condition: Chronic gingivitis -
A sore or loose tooth
A damaged tooth or inflammation of the tissue that holds it can give off a strong smell, and a cat chews carefully.
About the condition: Dental disease -
A wound or foreign object in the mouth
A stuck object, a wound or an ulcer in the lining of the mouth can become infected and smell.
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A growth in the mouth
A tumour or other growth in the mouth can give off a strong smell, and may also bleed or cause drooling.
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A more general illness
Some kidney, liver or other diseases change the smell of the breath. A vet finds this on examination and tests.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- When the smell appeared and whether it is getting stronger
- Whether the gums are red or swollen
- Whether there is a brown or yellow layer on the teeth
- Whether your cat eats carefully, drops food or tilts its head
- Whether it drools, rubs its face or grooms less
- Whether its thirst, weight or behaviour has changed
When to book a routine visit
Book a visit if your cat's breath is strong or does not change, or it chews carefully, drools or eats less. If it has not eaten for more than a day or its face has swollen, go the same day.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Chronic gingivitis Teeth and mouth The gums stay inflamed for a long time: they turn red, swell and bleed easily. The inflammation can drag on for weeks or months and make the mouth sore.
- Chronic kidney disease Kidneys and urinary tract A disease in which the kidneys slowly, over months or years, lose their ability to clean the blood and concentrate urine. It develops quietly, so its first signs are easy to put down to old age.
- Dental disease Teeth and mouth A broad name for problems with the teeth and the tissues that hold them: plaque and tartar, inflamed gums, loosening teeth and painful damage to the teeth themselves. It matters because a sore mouth affects eating, grooming and a cat's whole mood.
Body systems: Teeth and mouth Kidneys and urinary tract