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Why is my sweet cat suddenly aggressive and his behavior changed?

Updated On September 23rd, 2025

Pet's info: Cat | Domestic Shorthair | Male | neutered

Why is my cat suddenly aggressive? He was so sweet and only 4 days ago he was mean. He still is. I give him food, play with him do everything correct, and he is aggressive.

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1 Answer

Most Helpful Answer

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Answered By Megan, DVM, CVA

Veterinarian

Published on December 1st, 2017

There are several reasons for sudden onset of aggression including pain or infection somewhere, an increased thyroid hormone, or anxiety. If you want, you can try some feliway which is feline pheromones to help calm him. If This doesn’t work or if he stops eating or starts showing any other abnormal behaviors then I would have your vet take a look at him. Your vet will be able to ensure he doesn’t have an infection and they can even check his thyroid hormones of needed. If everything is normal, then talk to your vet about putting him in an anti-anxiety meds if needed. I hope this helps!

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