A 10-kilogram house cat that attacked a baby and trapped a family in a bedroom in Portland, Ore., has lashed out again, frightening new owners with his violent nature and jeopardizing his chance at finding a permanent home.

The couple who had taken in Lux the cat, whose violent tendencies have drawn notoriety in the U.S. and Canada, have given him up, said Jackson Galaxy, host of the show My Cat From Hell on the Animal Planet television channel.

In an episode of the show that aired last week, Galaxy diagnosed the cat with feline hyperesthesia syndrome, which can cause unpredictability, and prescribed medication to calm it.

Lux, a black-and-white Himalayan, made headlines and newscasts in March when he scratched a 7-month-old baby's face, prompting the father to kick the cat and barricade his family, including the dog, in a bedroom. The baby was not seriously injured but the family had to call 911 to have the police save them from the cat.

Portland Police Bureau spokesman Sergeant Pete Simpson said Lux was the most violent cat he had seen in his 20 years with the Portland police.

Since Galaxy's visit last month, the couple who adopted Lux found his violent tendencies to be too much.

Lux would unpredictably snap

"Unfortunately, as time went on, Lux's behaviour took a turn for the worse," Galaxy said on his website. "As he was settling in with Mollie and Jim, he would unpredictably snap - in essence, replaying the 911 nightmare I had originally walked in on."

Though the couple loved the cat, they couldn't keep him. Lux is now at an undisclosed foster home, according to officials at the Cat Hospital of Portland who are working to find him a home.

Galaxy said Lux has been responding to his medication and is doing better.

"I'm being cautious - can you blame me? Every single time I've made assumptions when it comes to Lux, I've had my lunch handed to me," he said on the website.

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5 tips for taming aggressive cats

There are many reasons a cat can turn aggressive, and there is no universal way to deal with it, Galaxy said. But the star feline behaviourist provided five ways to tame out-of-control cats:

  • Never leave a young child unsupervised with a cat.
  • Take it to a vet at least once a year. If a cat is acting suspiciously, the owner needs to pay attention. "Know what suspicious looks like," Galaxy said. "If they're not feeling well, cats will socially withdraw themselves, or they will lose weight, or they will gain weight, or they'll be howling in the middle of the night when they never did before.
  • Make sure cats can literally climb out of a situation. Having a space up high, like a cat condo, to get away from children and other pets is crucial, Galaxy said. "Make sure the cat can make the choice to get away from the kid," he said.
  • Timeouts are good things. "We associate timeouts with punishment, but in the world of cats, timeout is not a punishment." They can go to a designated place where they can settle down, come back to a peaceful moment or ground themselves, he said.
  • Stop fights between felines with "timeout drills." With simple pieces of cardboard, left strategically around the house, you can stop a fight between two cats. Put the cardboard between them, blocking their vision and providing a moment of disorientation when you can lead them to their timeout spot. It's especially important to have the drills with aggressive cats.