CHICAGO (CBS) — Veterinarians have warned pet owners to think twice before treating their dogs or cats with over-the-counter medication for fleas and ticks, as CBS 2’s Mary Kay Kleist reports.

Aundria Arlandson was forced to put down her family cat, Oliver, a few months after he was treated with Sergeant’s Flea and Tick Powder.

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“We called him jungle kitty. He just loved to play back there in the wooded area back there,” Arlandson said.

After taking Oliver on a trip outside, she spotted a tick on his back to get medication for him.

“You go to the store and you buy something; you see a name you’ve grown up with and trusted,” she said.

She picked out Sergeant’s Flea and Tick Powder, but within hours of using it on Oliver, the tremors started. Within a few months, her family was forced to put Oliver down.

“I told him that I wasn’t going to let it happen to another kitty and another animal ever,” Arlandson said.

Dr. Lisa Powell, a veterinarian, said, “This is why we don’t recommend using it.”

For years, Powell has told her patients not to buy such over-the-counter products after seeing some serious side effects.

“It can cause salivation, lethargy, vomiting, and then in the worst case scenario you can see seizures and even death,” she said.

Pyrethrins are the active ingredients in most of these products. They’re derived from chrysanthemums and research shows they can be toxic to cats.

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Last year alone, 39,000 complaints poured into the U.S. Environmental Protection Agency.

“These are pesticides. These are designed to kill things. So they’re to be taken very seriously,” said Marty Montell with the EPA.

The EPA told Arlandson that they’ve already been working on finding a fix for months.

“We’re on top of it. We certainly sympathize with those that have lost pets,” Montell said.

The EPA believes the real problem is people misusing the products – either putting too much on, or using products intended for dogs on cats.

Arlandson insisted she followed the directions.

Her family has a new cat now, but Arlandson said she doesn’t want other families to suffer such a loss.

“All I want is for it to stop. You know, Oliver died; he didn’t have to. If I hadn’t put that product on him he’d be here right now. I know that,” she said.

The EPA said it’s considering changes in regulations which could include new labeling and requiring products to be registered for just two years and re-evaluated.

The companies mentioned in this story said that safety is their number one priority and that the products are safe when used properly.

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For other treatment options and to find out what to do if your pet has an adverse reaction to these products, click here.