OPP say suspected carbon monoxide poisoning symptoms among a group of people turned out to be from a “marijuana laced brownie cake.”

Officers were called to a rental cottage in Northern Bruce Peninsula early Saturday after a group of vacationers fell ill.

Police found 10 people suffering from an “unknown affliction.” They discovered that one of the house guests had baked a brownie cake containing marijuana and everyone who ate some were feeling ill.

Northern Bruce Peninsula Fire department was also called in to rule out carbon monoxide poisoning.

Some of the house guests were taken to hospital to be treated. It was determined that the marijuana laced brownie cake was the cause of their illness.

No charges were laid.

“Police are warning those who choose to engage in the illegal and risky behaviour of consuming drugs, outside the guidance and direction of a physician, that the costs often out way [sic] the benefits,” said OPP in a news release.