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Kitten introduction: Aggression, stress, and diarrhea issues?

Updated On September 23rd, 2025

Pet's info: Cat | Domestic Shorthair | Female | spayed | 8 lbs

I'm trying to introduce my two kittens the new kitten is in our bedroom with everything he needs to be happy (litter food etc) and he keeps meowing to get out and when we try to introduce the kittens the youngest (female) keeps attacking the eldest male. What should we do? She keeps meowing to be let out of her room, we both give equal attention to both kittens and now the eldest kitten (male) suddenly has diarrhea with no change in diet, Please help!!

1 Answer

Most Helpful Answer

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Answered By Dr. Heidi DVM, CVA, CCRT, CVTP, CVSMT, CVCH

Veterinarian, Certified Veterinary Acupuncturist, Certified Canine Rehabilitation Practitioner

Published on July 25th, 2018

It sounds like you may be introducing the kittens too quickly. In order for an introduction to go smoothly, you need to be sure to introduce them gradually and allow both kittens time to acclimate to the change. Begin by keeping them in separate rooms with a door between them as you have been doing, so that they can smell one another through the crack under the door. After a few days of allowing this type of interaction, switch them for half an hour so that they are in the other’s environment and allowed to explore and smell. Several days later, allow them to see one another through a screen door or wire crate. If these interactions seem positive, eventually allow them to interact in a supervised area, but be sure that they both have the option of leaving if they become too stressed. One option for decreasing stress is to add a Feliway Diffuser ( https://www.feliway.com ) or Comfort Zone Diffuser ( https://www.comfortzone.com/ ) to your house. This is a calming pheromone that will work for a month and may be beneficial for both cats. I have also had luck with Rescue Remedy ( http://www.bachflower.com/rescue-remedy-pet/ ) which can be added to the water. There are a number of companies that make calming treats such as Composure ( https://www.petco.com/shop/en/petcostore/product/vetri-science-composure-feline-bite-sized-chews ). You could also consider calming music specifically for cats ( http://throughadogsear.com/tace/through-a-cats-ear-1-music-for-calming/ ). Good luck! I hope that was helpful. Thanks for using PetCoach.

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