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My cat has black mouth marks and bad breath. Is it cat flu?

Updated On September 23rd, 2025

Pet's info: Cat | Mixed Breed | Female | unspayed | 1lb

Hi, my cat had (they are now gone) two blisters inside the top of her mouth and really bad breath and was diagnosed with cat flu by the vet. She has black marks around her mouth and they seem to be getting darker. Is this due to cat flu? My vet does not seem to know. Thank you.

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1 Answer

Most Helpful Answer

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Answered By Christie Long, DVM

Veterinarian, Certified Veterinary Acupuncturist

Published on May 9th, 2018

Cat influenza is pretty rare, and your vet may have been referring to one of the more common viral diseases of cats that affects the upper respiratory tract and/or eyes, such as chylamidia, calicivirus, or herpes. Often these viral infections will produce secondary bacterial infections that respond to antibiotics, so this would definitely be indicated if it hasn't been tried. These viruses can also produce a condition in the mouth known as stomatitis, or severe inflammation of the gums and oral cavity, which often causes bad breath. Many times these cats need to have many teeth extracted in order to bring the condition into remission. I'd recommend seeing a specialist, or another vet who is familiar with these conditions and able to reach a definitive diagnosis and treatment plan. I would also recommend testing your cat for feline leukemia and feline AIDS, as these diseases can make cats more susceptible to other problems.

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