"Krokodil" is the street name for the semi-synthetic opioid derivative 
desomorphine. Although an old drug, it re-staged on "drug arena" during the last 
decade causing detrimental effects to its users. Despite the fact that Russia 
and other former Soviet Republics were the initial plagued countries, "krokodil" 
arrived in Europe and United States lately, as a substitute of the relative 
expensive, and in many cases unavailable, heroin. It can be easily manufactured 
in home-environment from codeine and causes significant health problems, even 
deaths worldwide. The aim of this review is to summarize the current knowledge 
about this drug, concerning its chemistry, synthesis, pharmacology and 
toxicology. Published or reported "krokodil" related cases, fatalities or 
intoxications, as well as self reports from drug users are reviewed. The 
existing analytical methodologies for the determination of desomorphine in 
biological samples as well as its legal status are also presented.