Hospitalization rates for accidental cannabis poisoning in kids increased two times more in provinces that legalized edibles: study

Three provinces that legalized cannabis edibles in early 2020 saw an increase in accidental cannabis poisonings among children aged 0-9 that was more than double that of Quebec, where edibles are prohibited, according to a new Canadian study.

Ontario, Alberta and British Columbia saw a 7.5 times increase in the rate of cannabis poisonings among young children after approving the sale of cannabis edibles compared to pre-legalization rates from 2015, while Quebec hospitalizations only increased threefold in the same time period.

“The goal of the study was to see how these hospitalizations for cannabis poisoning had changed following legalization of cannabis,” Dr. Daniel Myran, lead author of the study, told in a phone interview.

“And what we saw in our study is that the policy choices that were made by the different provinces had a very large impact on the changes in cannabis poisonings.”

The research, published Wednesday as a scientific letter in the New England Journal of Medicine, suggests that existing regulation may be failing in keeping these cannabis-infused products — which often come in the form of innocuous-looking gummies, chocolates or baked goods — safely out of children’s hands.


Cannabis legalization started in Canada in 2018, but a staggered rollout of products and regulation meant that only the sale of the dried cannabis flower was legal at first.

In 2019, as part of an update to the Cannabis Act, manufacturers were able to apply to become licensed to sell cannabis edibles, which hit shelves in 2020 within provinces that chose to permit their sale.

Myran, a public health and preventive medicine specialist and postdoctoral fellow at the Ottawa Hospital and the University of Ottawa Department of Family Medicine, said the new study results underline the impact of the sale of edibles when it comes to cannabis poisoning in children.

Prior to the legalization of edibles, the increase in cannabis poisonings was relatively even across the four provinces included in the study, with all four seeing more than a doubling in poisoning rates following the initial legalization of the dried cannabis flower in 2018.

“Quebec sees it, Ontario sees it, Alberta sees it,” Myran said.

But the picture changes after edibles were legalized in 2019, with the provincial data deviating starkly along policy lines.

While Alberta, British Columbia and Ontario broadly approved the sale of edibles, Quebec prohibited it, making it the perfect province to serve as a control for researchers.

“When the new products come to market, when the edibles come out, you have almost a tripling again in Ontario, Alberta and BC, and Quebec sees no further change, so it really isolates out the idea that legal edibles seem to be playing a pretty key role in these increases in poisonings,” Myran said.

The study looked at three time periods of hospitalization data for children aged 0-9 across the four provinces.

Researchers started with January 2015 to September 2018, before any cannabis had been legalized, then looked at the first period of legalization from October 2018 to December 2019. Finally, they looked at January 2020 through September 2021, when edibles had become legal in Alberta, Ontario and BC and were prohibited in Quebec.

There were 581 hospitalizations for cannabis poisonings in children aged 0-9 across the entire seven-year study period.

Myran clarified that they focused on the numbers of hospitalizations and don’t know the severity of individual cases or the outcomes.

“By virtue of being hospitalized, these were children that the treating team was quite concerned about and they had at least needed some form of observation,” he said.

“When young children consume a large quantity of cannabis, the very severe complication is they can stop breathing. And these are children that actually need to go to intensive care units and be supported on a ventilator. So it is a hundred percent a medical emergency if a young child has eaten a large quantity of cannabis. The effects that occur depend on the quantity of cannabis that’s consumed.”


One of the key details is that these hospitalizations are of young kids who were accidentally exposed to cannabis, researchers said, explaining that this is why they focused on children under the age of ten.

The average age of children hospitalized with an accidental cannabis poisoning in the study was three-and-a-half years old.

“It’s a pretty safe assumption that a three-and-a-half-year-old — and really up until, you know, 9, 10, 11 — that these kids are having an accidental ingestion, not purposefully ingesting cannabis to get high ,” Myran said.

This was something that regulators were concerned about from the start.

In order to mitigate the risks of children accidentally consuming these edibles, Health Canada stipulated a maximum of 10 mg of THC per edible package and also outlined that products could not be marketed or packaged in a way that looked appealing to young people.

But the trouble is, a cannabis-infused chocolate bar looks just like an ordinary one when it’s been unwrapped.

“Based on what these products look like when they’re out of their packaging, you cannot distinguish them from candy or other baked goods,” Myran pointed out.

It can also take longer for these products to kick in, with Health Canada noting that this latency period from consumption to feeling the effects can range from half an hour to four hours. This could mean that a child who comes across a bowl of gummies could consume a huge amount of cannabis quickly without feeling adverse effects right away.

“Are there long-term health implications of these kinds of events?” Myran said. “We just don’t know.”

When previous research from January showed that Ontario had seen nine times the amount of emergency department visits per month for cannabis poisonings in young children after cannabis legalization, there were too many unanswered questions to make a clear suggestion about policy, Myran said. It was unclear whether increases might involve the illegal cannabis market, or whether the pandemic was skewing results.

But with Quebec for comparison, it seems clear that legal cannabis edibles are playing a large role in these accidental poisonings among kids.

“The elegance of this experiment is that it really accounts for a lot of the noise,” Myran said.


Parents should be keeping cannabis products out of reach of children and retained in their original packaging, Myran advised, but he stressed that the increase in these hospitalizations can’t be seen as an individual responsibility.

“There’s a role for parental awareness and responsibility here, but given just the very, very high appeal of these products, if they’re seen and available to children, you don’t want to rely on people doing the right thing a hundred per cent of the time,” he said.

“We can clearly see from the results of the study that that’s not an effective strategy and that you need to think about other things like design, of how to make the products less appealing or different regulations to reduce these events.”

His big concern right now is those putting pressure on Health Canada for the 10 mg limit for edibles to be removed.

He’s concerned that increasing the potency of edibles without first doing anything to reduce the chances of children accessing them could have horrible consequences.

“One of the proposals that’s being made now as Health Canada revisits how we regulate these products is to get rid of that limit,” he said. “And you would worry that if we’re seeing this increase in poisonings with lower potency cannabis edibles that if you allow these things to be 10 times more potent, you might see a much higher number of poisoning events, and much more severe poisoning events .”

While not every province is likely to ban edibles, as Quebec has, it seems apparent that policy changes can have a measurable impact.

“I think that you have to have a conversation amongst regulators and … if there is a desire from the regulator to continue to see edible products being offered, there are ways that you can change what’s currently being offered that it meets the demands of adult consumers without creating a large risk or a large attraction to younger children,” Myran said.

Prior to the legalization of cannabis, a concern for children was often used as a reasoning to keep the drug illegal, but this type of research doesn’t support that, Myran stressed.

“Before we proceeded with legalizing cannabis, there were enormous social and public health harms that occurred because of our drug-policy approach to cannabis,” he said, pointing out that Black and Indigenous youth were highly overrepresented among those criminally punished for minor use possession . “Legalizing cannabis with very strict regulations, or just decriminalizing, it has important public health benefits.

But while decriminalization of cannabis has had beneficial impacts, proper regulation is important to protect everyone.

“What I would argue is you can achieve those public health benefits through decriminalization or through strict legalization. You do not need to have highly commercialized cannabis products to get those benefits,” he said.

“I think that what this study is highlighting is that this is a clear example of a harm that has occurred from legalization without sufficient regulation.”