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My cat is sad, sleepy, and vomiting after vaccines. Is this normal?

Updated on September 23rd, 2025

Pet's info: Cat | Russian Blue | Male | unneutered | 1 year and 8 months old | 3 lbs

My cat got his vaccines two days ago and since yesterday I see him sad, sleepy and doesn’t want to eat, today he threw up. It’s that normal or I really have to worry about it?? I don’t like to see my cat like this.

3 Answers

Most Helpful Answer

Answered By Destini R. Holloway, DVM

Veterinarian

Published on January 29th, 2019

I am so sorry that your cat Milo is ill following vaccines. These are classic signs for a vaccine reaction, and therefore I recommend having him seen by your vet right away. If you vet is currently not open, then I would consider taking him to your ER vet to make sure he is stable and ok. He will likely get medications (antihistamine +/- steroids) to help combat the reaction.
I do hope that your pet Milo is able to make a full and speedy recovery. I would notify your vet about this as soon as you can so that precautions can be taken next year when he is due for his vaccine boosters to help prevent this from happening again. Best of luck and take care!

1Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Catherine Stecyk
Veterinarian
Published on May 12th, 2019
Hello and thank you for reaching out to Petco Pet Education Center, formerly Petcoach. It is not unusual for pets to be extra sleepy for 1-2 days following vaccines and vet visits, partially because of the vaccinations but also because of the stress of a vet visit. If your female cat continues to be lethargic and/or does not want to eat for longer than this time, she should be seen by your veterinarian for evaluation, as something else may be going on. I hope this is helpful!
1Pet Parents found this answer helpful
Answered By Dr Stafford, BVetMed, MRCVS
Veterinarian
Published on July 5th, 2017
Vaccines can make cats very sleepy and dull for a while after, especially an older cat. This should pass in a few days. However if Milo seems very poorly or doesn't improve I would visit the vet in case something else is going unrelated to the vaccines.
1Pet Parents found this answer helpful

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