Instructions
Avoid initiating rough play. While playing rough may seem harmless, this actually sends mixed messages to the cat as it interprets your actions as approval of playing rough.
Make a high-pitched noise, followed by saying "No" in a firm voice that is different from your usual tone. The cat responds to the difference in your voice by calming down. In order for this method to be effective, change the high-pitched noise each time it begins to act aggressively. Do not say the cat's name when reprimanding it, as this causes confusion.
Ignore the cat for up to 15 minutes after reprimanding it to change its violent behavior. The cat should stop being aggressive after two weeks if you use the reprimand and ignore technique consistently, according to Vet Info.
Include a treat along with the object that causes the cat to behave aggressively. A fearful cat attacks in defense, but when provided a treat along with the fearful object the cat is conditioned to associate the object with pleasure, according to the shelter medicine program at Cornell University's vet school.
Redirect the cat's energy by playing a game of catch. Toss a tennis ball for your cat to retrieve, and reserve the same time every day to play with your cat. The catch game expends the cat's energy, which reduces the likelihood of it being violent due to pent-up energy.
How to Change Aggressive Behavior of a Cat
An aggressive cat is not only annoying, it can cause physical pain and damage to the home if it is allowed to continue behaving in a violent way. Cat aggression is often seen in kittens who were taken away from their mother at an early age, which prevents them from learning how to deal with aggression. On the other hand, a violent cat may be acting that way due to physical pain and requires immediate medical care.