Use of a a flesh-eating heroin substitute that rots the skin of addicts has now spread to a Chicago suburb, according to local media reports.

Krokodil, which is considered more addictive that heroin, originated in Russia before cases were seen in Arizona last month.

The latest reports of three cases at the Presence St. Joseph Medical Center in the Joliet suburb of Chicago, is likely to spark further fears that use of the drug, which usually kills addicts within two years, is spreading in the US.

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According to NBC Chicago Dr. Abhin Singla of Presence St. Joseph Medical Center said the treatment facility this week saw three patients who said they used the drug.

The substance, which is similar to morphine, is an ultra-cheap heroin substitute that counts crushed codeine pills, gasoline, cooking oil, iodine, paint thinner and lighter fluid among its toxic ingredients.

Users of krokodil or "crocodile" can suffer horrific effects including rotting sores, gangrene and abscesses. It acquired its name because of the reptilian scaly effect it causes on human skin.

“If you want to kill yourself, (using) this is the way to do it,” said Dr. Abhin Singla, director of addiction services in Joliet.

“It’s about three times more potent than heroin, but the ‘high’ lasts only for a few hours,” Singla told the Chicago-Sun Times.

According to the newspaper a dose of crocodile costs about $8, while users pay $25 to $30 for heroin.

The average krokodil user has a life expectancy of just two to three years after they start taking the drug, and in that time they can expect their skin to turn green, scaly and fall-off as a kind of pre-death decomposition sets in.