The meme of the randomness of cats is so popular you may not often look for a deeper explanation. But when your cat appears to “randomly” attack another pet or human family member, you need to understand what’s going on and what to do next.
Not Random, Redirected
“Redirected aggression” is aggression directed toward something other than the trigger for the aggression. For example, your cat thinks “I want to chase away that weird cat outside but I can’t get to him! I’ll just smack you instead!” A cat becomes upset or frightened by something they can’t reach and turns that frustration or fear on the first animal or person that they can reach.
You might also see a cat who turns on their housemates when startled or frightened by something they don’t understand or can’t see, like a loud noise. This may be more accurately called “misdirected aggression” but can be handled similarly so we’ll just lump it in here.
Redirected aggression is most often characterized by sudden aggression (biting, scratching, swatting, chasing, etc) toward a nearby human or animal. You’ll see an attention shift from a trigger, usually something outside the house or room, to the target. If you can’t see a trigger or don’t know to look for one, redirected aggression often looks random as the target may not have been interacting with the cat in any way.
Not Playful
This isn’t the same as a cat that pounces, swats, or bites to solicit play. While this type of playful aggression can also seem random, it is usually identified by quick back and forth movements, pauses, and is repeated in the morning and evening or whenever something interesting moves past.

Check with the Vet
If your cat’s aggressive behavior is new, happening more frequently, and/or has no trigger that you can see, schedule a vet visit to check for health issues. Redirected aggression is a one-time event related to a specific trigger. Though tension and conflict may continue between pets afterward, increasing or repeated events may point to some other problem.
How to Handle Redirected Aggression
So redirected aggression isn’t really random but it can be completely unexpected and scary. Your first response can have a big impact on how your cats recover.
Right Away
Immediately put the offending cat in a safe space with the lights turned down low, curtains closed, no loud noises, and no other pets and people in the area. This is to minimize the risk of continued aggression while they calm down. Remember, they aren’t being randomly terrible, they’re reacting to something that has made them very upset or fearful. They can’t learn any lessons in that state so there’s no point in punishing them.
If you can’t move the cat to a quiet place, move everyone else out. Don’t try to pull a stressed cat out of a hiding place or otherwise force an interaction. Just do whatever is possible and least stressful to put some distance and doors between the cat who had the aggressive reaction and their victim.
After Things Have Calmed
Once everyone has calmed down, give any pet involved a play session and some treats to help them feel normal again. Don’t move forward until all humans and pets have had a chance to completely relax again.
Let the offending cat come back to where the incident occurred but keep all other pets and people away. Keep curtains or blinds closed if there was any chance that something outside triggered the aggression. Allow them to explore and offer play and treats in the areas where they had the reaction. Now put this cat in a separate room and allow the victim to come back into the space and explore or play too. Again, you’re waiting for everyone to return to normal.
Slowly bring the family back together. First allow the offending cat to interact with any other people or pets, one on one, with the victim being last. Use play and treats to keep the interactions positive and be ready to redirect and/or separate the cat if things seem at all tense.
Repeat As Needed
Depending on the intensity of the aggressive incident and how quickly all family members seem to be returning to normal, you may need to repeat these steps several times over the next few days. Supervise your cat when they are with other pets and separate them if you can’t. It’s extremely important to prevent further incidents during this recovery phase so don’t be afraid to be proactive.
Longer Term
Some cats bounce back right away with no issues. Others don’t. If your cats are still having issues after a few days, you may need to do a more complete reintroduction. First separate the cats into different parts of the house, each with everything they need to live happily but with no way to get to one another. Give them time to settle in and behave normally (think days, not hours). Then beginning a slow and controlled introduction process as described here. If your issue is between a cat and dog, you can do the same thing (give the pets a break from each other) and then refer to this page for more information.
An Ounce of Prevention
Finally, take a moment to consider whether you can proactively prevent this type of problem in the future. Some things can’t be eliminated (accidentally dropping a stack of pans) but you could work on desensitizing your cat to loud noises so they don’t react as strongly in the future. Desensitization requires the noise never be loud enough to frighten your cat even as it is very gradually increased. Now that you know your cat has such negative reactions to triggers, proceed with desensitization very carefully! Consider hiring a professional to help you get it right.

Other triggers can be managed more directly. Outdoor cats are a common trigger for indoor cats. Keep blinds closed, cover windows with opaque film, or use humane deterrents to prevent your cat from seeing these strangers in your yard.
Aggression is rarely random; when you look closely you’ll find an explanation and a plan for the future. Acting immediately and using positive techniques of play and treats will help you overcome redirected aggression.
Aggression is a serious issue. If you are seeing continued issues, consider scheduling a private behavior consultation.