How to Stop Aggressive Cat Behavior Towards a New Cat

It may take time for your cat to become best friends with the new kitty.

It may take time for your cat to become best friends with the new kitty.

You brought home an adorable kitty, but your other cat isn't exactly thrilled with the new arrival. She's doing everything in her power to defend her territory and make the adopted kitty feel unwelcome. It may have begun with hissing, chasing and swatting, which escalated into more serious attacks between the two sparring felines. The new kitty may try to hide from your pissed-off pussycat in other parts of the house, too frightened to emerge to even use the litterbox. Can't we all just get along?

Items you will need

  • 2 cat toys
  • String

Step 1

Place the fighting felines in separate rooms, each with their own comfortable sleeping areas, litter box, water and food. Keep the doors closed so they can't escape and have interaction with each other. If the rooms are adjoining, seal off the bottom of the door so they're unable to paw or detect each other's scent. Keep them in separate rooms for a few days, giving them time to calm down.

Step 2

Switch the perturbed pussycats' rooms so they're forced to reacquaint themselves with each other's scent. Expect them to initially show how much they dislike this new living arrangement with hissing, angry meows and other forms of feline acting out, because the odors bring back unpleasant memories of their earlier time together. Rotate the rooms back and forth for a few days so the cats learn to tolerate their enemy's smell.

Step 3

Place the kitties in adjoining rooms so they can only eye each other through a slight opening in the door without physical contact. Make it a pleasant experience for them to be in close proximity. Feed them delicious food and give them interactive toys to play with. Use a string to tie two interactive cat toys together and slide them under the adjoining door so they can share playing with them. Leave them in the connecting rooms for a few days so they can learn that being close to each other is tolerable and even fun.

Step 4

Put the kitties on opposite ends of the same room, either restrained with leashes or in animal carriers. Feed them their favorite foods and play with them so they begin to associate contentment and pleasure while being in each other's presence. Move them closer at the next feeding session if they continue to appear relaxed. If one or both cats displays anxiety or fear, move the carriers apart and repeat the process until the cat has calmed down.

Step 5

Release the former feline enemies from their carriers and feed them, but continue to keep them far apart in the room. Gradually move them closer as the cats' anxiety decreases and any aggression has vanished. Allow them to be together for a few minutes at first, and then gradually increase the time until they're comfortable with each other and the reconciled tabbies are singing "Kumbaya."


  • The process can occur quickly or take weeks or months, depending on the personalities of the two cats. If your cat's aggression toward a new kitty can't be controlled, take her to a vet for a checkup to rule out any medical conditions that may be causing the behavior.

About the Author

Liza Blau received a B.A. in English from Columbia University. Her writing has appeared in fiction anthologies from Penguin Press, W.W. Norton, NYU Press and others. After healing her own life-threatening asthma by switching to a whole, natural foods diet, she founded the NYC Asthma Wellness Center. Blau counsels individuals on healing their own asthma and allergies with dietary and lifestyle changes.

Photo Credits

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