A seven-month-old baby was among a “significant” number of children requiring medical care for “serious adverse events” involving cannabis since legalization last October, according to a new study.

Between September and December 2018, 16 cases were reported to the Canadian Paediatric Surveillance Program (CPSP), forming the start of a two-year study.

Cases involved children ranging in age from seven months to 17 years, with an average age of nine. Of those hospitalized, almost two-thirds were due to kids accidentally ingesting cannabis belonging to a parent or caregiver.

"The number of cases involving young children is striking," Dr. Christina Grant, a pediatrician in Hamilton, Ont. and co-principal investigator, said in a news release.

“Almost 70 per cent of the young people who needed to be in hospital is because they accidentally ate a cannabis edible and then became really intoxicated and overdosed,” Grant told CTV News.

The CPSP began a new study on serious and life-threatening events associated with recreational cannabis use in Canadian children and youth in September 2018.

The data is similar to trends in Colorado and Washington state, where cannabis is also legal, the CPSP said.

A Manitoba mother, who asked not to be identified, went through a harrowing experience when her five-year-old son grabbed a cannabis-laced chocolate bar from a top shelf in the kitchen and shared it with his two-year-old sister.

The little girl started having seizures after consuming some of the chocolate in February. She was rushed to hospital, where she was put on a breathing machine and spent three days before she recovered.

“There is quite often that I think about that day and I still cry about it,” the mother told CTV News. “I want other parents to know to keep (cannabis edibles) locked…It is very serious, someone could die from this.”

Grant said the number of cases identified in the CPSP study so far is just “the tip of the iceberg.”

“These are 16 children who had to actually be admitted to hospital beyond needing to come to the emergency room,” she said. “We are not talking about all the other cases of kids who needed to come to emergency rooms or see their physicians for accidentally consuming cannabis.”

“Young children will put anything in their mouths and these cannabis edibles are very attractive, they look like candies, gummy bears or a cookie,” Grant added.

The study will continue until October 2020 and will monitor trends following the legalization of edibles in the fall.

The Montreal Children’s Hospital issued an alert in May, warning that cannabis intoxication was on the rise among children since legalization. The hospital said that children who accidentally ingest cannabis may experience more severe symptoms than adults.

“People need to be really conscious of the impact it can have, particularly on young children given their size and the way they metabolize (cannabis),” the hospital’s trauma director, Debbie Friedman, told CTV News this week.

She said the dangers of cannabis for kids need to be addressed in the packaging of cannabis products and by educating parents about proper storage.

Last February, the CPSP recommended to Health Canada that any product resembling candy or appealing to children be prohibited and that packaging include warnings about known and potential harms to young children and fetuses from cannabis exposure.

Health Canada's final regulations on cannabis edibles were announced on June 14, with the new rules taking effect Oct. 17.

The regulations require child-resistant and plain packaging for edibles and a 10 mg THC limit per product.

THC is the part of cannabis that makes users feel high.