"In the last three to five years an increasing number of reports suggest that people who inject drugs (PWID) in Russia, Ukraine and other countries are no longer using poppies or raw opium as their starting material, but turning to over-the-counter medications that contain codeine (e.g. Solpadeine, Codterpin or Codelac). Codeine is reportedly converted into desomorphine (UNODC, 2012; Gahr et al., 2012a, 2012b, 2012c; Skowronek, Celinski, & Chowaniec, 2012). The drug is called Russian Magic, referring to its potential for short lasting opioid intoxication or, more common, to its street name, krokodil. Krokodil refers both to chlorocodide, a codeine derivate, and to the excessive harms reported, such as the scale-like and discolored (green, black) skin of its users, resulting from large area skin infections and ulcers. At this point, Russia and Ukraine seem to be the countries most affected by the use of krokodil, but Georgia (Piralishvili, Gamkrelidze, Nikolaishvili, & Chavchanidze, 2013) and Kazakhstan (Ibragimov & Latypov, 2012; Yusopov et al., 2012) have reported krokodil use and related injuries as well."

Source

Grund, J. -P. C., et al. "Breaking worse: The emergence of krokodil and excessive injuries among people who inject drugs in Eurasia." International Journal of Drug Policy (2013), http://dx.doi.org/10.1016/j.d…
http://www.ijdp.org/article/S…