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Why does my 9-month-old cat have a swollen, red mouth and bad breath?

Updated On September 23rd, 2025

Pet's info: Cat | Domestic Shorthair | Male | neutered | 9 months and 17 days old

Hello, my 9 month old cat has developed some sort of infection in his mouth. Please advise what possibly could this be, infection or bad tooth!? Side of his mouth is red, a bit swollen and definitely bad breath is present.

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1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on April 18th, 2018

I would say from your pictures that Jax's gum is quite swollen and I imagine it's very painful to him. It could be that his tooth has broken off and is rotten causing the swelling and bad breath. It could also be he has a tooth root abscess. This is definitely something that needs to be treated sooner rather than later, so please call your vet to get him an appointment asap to have this treated. I would soak his dry food in warm water or gently warmed chicken broth to make his food softer to eat, or you can give him canned food for now. Best of luck, I hope this helps.

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