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Why is my kitten's poop watery after vaccinations and flea treatment?

Updated on September 23rd, 2025

Pet's info: Cat | Domestic Mediumhair | Male | neutered | 4.8 lbs

My kitten got his final shot on Tuesday. He has had very watery stools. I don't know if he reacted to his first shots because he got them before he became mine. He seems fine. He's playful and eating and drinking water. He also had his first flea treatment.

3 Answers

Most Helpful Answer

Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on August 5th, 2017

Vaccines can give a kitten diarrhea for a day or two afterwards, and it's a good since that he is otherwise acting normal. It could also be that he has intestinal worms, and I would make sure he is up to date on his deworming treatments. Panacur is a brand I recommend to give to kittens, it's a three day course of treatment you can get OTC from a pet store or your vet's office. You would have to give Henry a second course of the treatment two weeks after the first ends to kill all the worms. He should then be dewormed every month until he is six months old, and then every three months thereafter. If he is up to date on his deworming treatments and the diarrhea doesn't clear up in 48 hours, then I would take him into the vet for an exam. You can try feeding him a bland diet of boiled white meat chicken (no bones) in small amounts to see if that helps as well. If it does help, continue the bland diet for a couple of days, and then start slowly adding back in his normal diet. I hope this helps!

1Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Andrea M. Brodie, DVM
Veterinarian
Published on April 17th, 2018
Your kitten can be dewormed at this age. The diarrhea should go away by itself, , however feed small amounts of good quality kitten food often (start with 6 times/day, Dry food is not suitable for kittens. I would worm him now and take him for his first shots in about two weeks , once the diarrhea is gone. Make sure he is well hydrated, You can replace one or two of the solid meals with some kitten milk. He is still very young, and really should not have been taken from his mommy before the age of 12 weeks.
1Pet Parents found this answer helpful
Answered By Dr. Melanie, BVSc MS
Veterinarian
Published on June 16th, 2018
Gizmo is very cute! It could also be that he has intestinal worms, which are common in kittens, causing his diarrhea. I would deworm both him and his siblings with a dewormer called Panacur. You can get it from your vet. It's a three day course of treatment, and they will all need another course of treatment two weeks after the first to kill all the worms. They should then be dewormed monthly until six months of age, after which they should be dewormed every three months.

Now if he's up to date on his deworming treatments, I'd make an appointment with the vet for Gizmo. Diarrhea can be very dehydrating in young kittens, and this should be examined and treated. Call the vet on Monday in this case. Best of luck, I hope this helps!
1Pet Parents found this answer helpful

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