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My cat won't eat after vaccine. Is this normal or should I worry?

Updated On September 23rd, 2025

Pet's info: Cat | Mixed Breed | Female | unspayed | 1 year and 8 months old

My cat has not eaten for 24 hours after her vaccinations

4 Answers

Most Helpful Answer

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Answered By Dr. Tristan Wilhelm, DVM

Veterinarian

Published on December 20th, 2015

Some poor appetite can be considered normal after vaccinations. Vaccines stimulate the immune system to help protect your pet from common diseases they could be exposed to. Vaccines can sometimes cause minor changes in appetite or behavior. Usually I tell clients some decrease in appetite and decreased activity can be normal for 24 hours but for any issues lasting more than 24 hours they should call me ASAP. Some of the major issues (although rare) associated with vaccine reactions are trouble breathing and anaphylactic shock. If you notice any trouble breathing, severe lethargy or swelling of the face or at the vaccine site you should contact your veterinarian as soon as possible. If the poor appetite is still an issue after 24 hours or If any other issues are going on contact your veterinarian ASAP.

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13Pet Parents found this answer helpful

Other Answers

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    Answered By Dr. Strydom, DVM

    Veterinarian

    Published on July 19th, 2018

    Hello, thank you for using Petco Pet Education Center, formerly Petcoach. So sorry Trixie is having this issue. Yes, she is likely having a delayed hypersensitivity reaction to the vaccines. If her symptoms don't resolve (or get worse) in the next 24 hours you should take her back to your vet for a follow-up. Do not give her any over the counter medications. Just let her rest and offer her food and water as normal. Hope this helps. Best wishes.

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    1Pet Parents found this answer helpful

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    Answered By Steve Popish, DVM

    Veterinarian

    Published on September 13th, 2017

    Sorry about your young cat. Reaction to vaccinations are not uncommon and can often result in fever, muscle soreness, and lethargy. Vomiting can occur as well and good to have some medication aboard from recent visit. Good that your cat is drinking and maintaining hydration but the appetite is still a concern. Probably ok to wait until tomorrow to take back to your veterinarian. In the meantime, try small amounts of canned food to stimulate appetite. If no luck by then, check in with your veterinarian and see if there might be another cause for the vomiting and not eating. Hope this helps, please reach out if you have additional questions. Thanks and good luck, Steve Popish, DVM

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    1Pet Parents found this answer helpful

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    Answered By Lauren Jones VMD

    Veterinarian

    Published on March 17th, 2017

    Poor Pancho! A bit of lethargy can be normal for a day or two after vaccines. If Pancho is also experiencing vomiting, diarrhea, hives or facial swelling, he should be seen by a vet immediately, as this could indicate an allergic reaction to his vaccinations. Try to coax him to eat tonight, but if he won't eat by tomorrow, take him to your vet. Cats can develop a condition called hepatic lipidosis (fatty liver disease) if they go without eating for an extended period of time. I hope he feels better soon!

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