A new study from researchers at the Oregon Health and Science University shows that the number of calls to poison centers across the country for children suffering adverse effects from taking marijuana surged by 245% over the last two decades.

The results were published in the peer-reviewed journal Clinical Toxicology.

The team of researchers analyzed over 338,000 reports in the National Poison Data System from 2000 to 2020 and saw a massive uptick in reports of children consuming marijuana. Most of the calls to poison centers involved edible marijuana products. It is unclear how many of the reports involved accidental ingestion.

The increase comes as dozens of states have legalized marijuana for both medical and recreational use.

"Marijuana is readily accessible, in multiple forms, whether at a store, from a friend or relative, or online," ABC News medical contributor Alok Patel said.

The most reported substance over the 20-year period was dextromethorphan, which is the active ingredient in cough syrup. However, reports to poison centers for the drug peaked in 2006 and have been declining ever since.

The number of reports of alcohol misuse or abuse among children also declined, with the highest number reported in 2000.

While the number of calls about marijuana remained steady from 2000-2009, they started to rise in 2011. The most significant increase in calls occurred during the final three years of the study, from 2017-2020.

"Our study describes an upward trend in marijuana abuse exposures among youth, especially those involving edible products," said Dr. Adrienne Hughes, Assistant Professor of Emergency Medicine at Oregon Health & Science University and one of the authors of the study. "These findings highlight an ongoing concern about the impact of rapidly evolving cannabis legalization on this vulnerable population."