It was no treat for a St. Catharines mother who discovered over the counter medication in her son's Halloween candy bag.

Sarah Stevens tells 610 CKTB news, when she went through the candy her six year old son brought home Wednesday night after trick or treating in the city's south end, she discovered three packages of pain medication, including Advil liquid gels and Robaxecet, a pain reliever for back pain.

Stevens says her son went with his older brother and some of friends, along with her husband, and he was the only one given the pill packets.

"What was most disturbing about this is that these packets looks very similar to those Swedish Berries packs, or one of these small packs (of candy) given out regularly on Halloween," says Stevens.  

She has contacted Niagara Regional Police but was told its hands were tied, as it would be near impossible to track down which house gave out the pills. 

"I know that they need a crime to be committed but I was told unless my child had become sick, that really nothing could be done about this and no investigation would be made."

Stevens believes parents should at least be forewarned so they can check their child's bag of goodies and make sure there is nothing in there that can be harmful.

She's adiving all parents to thorougly check their children's candy before allowing them to dig in to the treats.

In London, police there issued the same warning after a child was given a razor blade wrapped in wax paper while out trick or treating.