CHICAGO (AP) — Illinois officials are issuing a new warning about deadly forms of synthetic drugs cropping up nationwide.

Illinois Attorney General Lisa Madigan’s office and the Illinois Poison Control Center released a joint alert on Thursday following an increased number of hospital visits and deaths linked to what is known as “spice” or “K2.” Those are street names for types of synthetic marijuana that mimic the effects of the active ingredient in marijuana called THC.

Madigan says that ingesting a package of synthetic drugs is like “playing Russian roulette” because of the deadly risks. She says there’s no way to determine what chemicals have been used in making the drugs and in what amounts.

Synthetic drugs are banned in Illinois under a 2012 law.