How to Stop a New Cat From Being Aggressive to Other Cats In the Home

A successful introduction can help your cats become comfortable with each other.

A successful introduction can help your cats become comfortable with each other.

Whether fostering, pet-sitting or bringing a new cat into your home, take steps to ensure a successful introduction. Reducing or eliminating aggression between the cats from the very beginning can set the tone for a good bond between the cats later and avoid long-term negative effects in your cat household.

Set up a secure room for the new cat. Fill a water bowl, food dish and litter pan for the new cat. Place these items in a room where your new cat will live for at least the first week. The room should have a door that latches securely so that the new cat will stay in and the household cats will stay out. This will give your new cat time to become settled in the new environment and reduce aggression between the cats.

Encourage the cats to smell each other. Pet the new cat and immediately after, pet the household cats. Do this several times a day. Brush the cats with the same brush. Allow the cats to sniff each other under the door of the new cat's room. Allow the cats to smell each other, but not see each other, for at least one week.

Move all cats to a neutral space for their first face-to-face introduction. If there is not neutral space in your home, consider taking them to your car or to a friend's home for the introduction. Break up any fights immediately by spraying the fighting cats with water. Give the cats treats and attention together in the neutral space.

Open the door between the new cat's room and the rest of the house. If there is no aggression and the cats seem to tolerate each other, you can allow them to live together permanently. Keep an eye on the cats for the first few days.

Items you will need

  • Litter pan
  • Food dish
  • Water dish
  • Spray bottle


  • If the new cat or the household cats are showing severe signs of aggression and stress, consider using a plug-in diffuser with simulated cat hormones like Feliway Comfort Zone.
  • If the cats start becoming aggressive once you have started to introduce them, go back to keeping them in separate spaces.
  • Get your cats spayed or neutered. This can significantly reduce aggression in cats.


  • If you let a cat become overly aggressive with another cat, it can not only lead to injuries, but it can ruin the relationship between the cats forever. If your cats are being aggressive, try to separate them and take the introduction process slower.

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About the Author

Kayla Richard has been writing from Rochester, N.Y., since 2007. She holds a Bachelor of Arts in English writing arts from SUNY Oswego and a graduate certificate in nonprofit management from SUNY Brockport.

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