With cannabis legalization looming, doctors foresee uptick in emergency-room visits

Cannabis can be more potent today than it was 20 or 30 years ago, says Ian Culbert of the Canadian Public Health Association. One of the biggest causes of poisoning is that the concentration of the active ingredient in marijuana, tetrahydrocannabinol (THC), can vary widely, from less than 5 per cent to more than 40 per cent. While cannabis plants can be bred to have different concentrations of THC, the bigger concern is the unregulated world of edibles – cookies, chocolates and more – that contain THC oils.

As a result, it can be easy to overdo it.