Police are warning Toronto dog owners to be wary of treats left in parks after a dog became violently ill over the weekend.

Officers said a man was walking his dog in the area of Thorncliffe Park Drive and Overlea Boulevard on Friday, at approximately 12:30 p.m. The man noticed his dog picked up a green, stick-like object, and began to chew it.

The man realized it was a dog treat, and removed it from the pet's mouth before it could eat the entire thing. When the pair got home, the dog was violently ill, police said.

The owner suspected the dog treat was behind the sudden illness, so he returned to the area to look for more. When he arrived, he found several of the green objects on the ground in Thorncliffe Park, police said.

The treats are described as 13-centimetre-long green sticks that have a strong chemical smell. Police said there is concern that pets or children may eat the treats and fall ill.

Anyone with more information is asked to contact police at 416-808-5300 or call Crime Stoppers anonymously at 416-222-8477 (TIPS).