Dr. Abhin Singla, director of addiction services at Presence St. Joseph Hospital, said three women and two men arrived in the hospital's emergency room last week with rotting flesh, the Chicago Tribune reported.
All of the patients reported using krokodil -- a drug made by mixing codeine, red phosphorous, iodine and paint thinner together that was first seen in Russia 11 years ago.
The drug gives users a heroin-like high, but leaves them with rotting wounds and scaly, green flesh.
"It is a horrific way to get sick. The smell of rotten flesh permeates the room," Singla said in a news release issued by the hospital. "Intensive treatment and skin grafts are required, but they often are not enough to save limbs or lives."
Dan Bigg, director of the Chicago Recovery Alliance, which serves thousands of drug users at needle exchange clinics, says the wounds of krokodil users are common among users of other injectable drugs.
"In 24 years of almost daily contact with opiate users, I have never seen it, nor have I heard of anyone who has used it," Bigg said. "There would be no reason to use it here. Codeine is not readily available. Heroin is easily available, and costs $5 or $10 (per dose). Why would someone want to mix gasoline with their drugs if they didn't have to?"
Health authorities have not yet confirmed the krokodil cases.