A Vancouver Island woman is raising concerns with legalization after she says her dog ate discarded marijuana on a BC Ferries vessel and went into seizures.

Alyx Speth said she was travelling with her five-month-old French bulldog, Leon, on a BC Ferries sailing from Vancouver to Victoria earlier this month.

They were in the pet-designated area below deck when she says Leon began to sniff around – and ate pot left on the ground from a previous sailing.

She said she tried to get as much of it out of his mouth as she could, but the dog swallowed some of the soon-to-be-legalized drug.

"He started having seizures and tremors and his eyes were rolling back in his head," Speth told CTV News Monday. "I was bawling my eyes out. I thought he was going to die."

The dog was taken to an emergency veterinary clinic when the vessel docked, and due in part to an overnight stay Speth said the bill cost her nearly $1,000.

In an email to BC Ferries, Speth claimed the pet room on the vessel wasn't swept out before her sailing. She said she's now considering legal action to cover the cost of her vet bill.

BC Ferries has yet to return CTV's request for comment.

It isn't the first time a dog has ingested pot found on the ground.

Victoria resident Mike Knippel said his pooch, Hilo, nearly overdosed on pot he ate off the ground a few months ago.

"It looked like he was going to tip over. His head shied away from our hands when we went to pet his head," said Knippel. "So being 12 years old, we of course thought the worst, thought maybe stroke or seizure or something like that, so we took him to the vet."

The vet told Knippel that his pet was stoned, and also mentioned he's seen an increase in dogs accidentally eating cannabis.

THC, the psychoactive ingredient in cannabis, is toxic to animals and especially dogs, according to veterinarians.

Vets say stoned pets will likely become more common when the drug is legalized this October.

"You're going to see dogs that are very wobbly, they're losing their coordination, or even to the extent of being comatose," said veterinarian Dr. Evan Bell.

Speth says she wants other pet owners to be vigilant so they can avoid the same fate.

"I'm concerned that it's going to be everywhere and dogs are gonna ingest it, cats are gonna ingest it, and there's going to be fatalities," she said.

Marijuana will become legalized in Canada on Oct. 17.