SPRINGFIELD, Ill. (AP) — Illinois public health officials say the number of people in Illinois who have experienced severe bleeding after using synthetic marijuana has increased to 81 cases.

Wednesday’s updated number includes two deaths and is up from 56 cases reported Monday. Health department data show the majority of cases are in the Chicago area, Peoria County and Tazewell County. Some have tested positive for an anticoagulant often used as rat poison.

The substance is often referred to as Spice, K2 or fake weed. It is a human-made, mind-altering chemical that is either sprayed on dried shredded plant material to be smoked or sold as a liquid to be vaporized and inhaled. Public health officials say the product is not safe and if anyone has purchased it they shouldn’t use it.