Cases of cannabis poisoning increased after legalization and decriminalization of the drug, according to a new meta-analysis published in the journal, Addiction.

“The likely explanation is that legislation has increased the use of cannabis, which has also increased poisoning.” senior author, Dr. Rose Cairns from the University of Sydney, said in a statement.

There’s also the possibility that changing the laws added an element of confusion to the public, Cairns continued. Consumers might assume that if marijuana is legal, it must mean the drug is safe, she said. However, that is far from true.

“Increased availability and use of edibles (gummies and chocolates, for example) appears to be an important driver of the increase in poisonings, particularly among children,” said Cairns. “Edible cannabis has a higher risk of poisoning because people tend to consume larger quantities, and the effects of cannabis take longer to show up when ingested than they do when smoked. This is concerning because edibles are especially attractive to children.”

Cannabis poisoning sets in when smokers inhale too much of the drug too quickly. It also occurs when consumers feast on drug-infused edibles with high concentrations of tetrahydrocannabinol, or THC. The Centers for Disease Control and Prevention (CDC) warns symptoms like trouble walking, sitting up or even breathing can come on quickly or slowly depending on the source, and may take hours to subside. In some instances, emergency hospitalization is required.

The CDC also points out that the majority of poisonings are attributed to edibles. For this reason, study authors say children in particular are at greater risk.