BACKGROUND: Krokodil, a homemade injectable opioid, gained its moniker from the excessive harms associated with its use, such as ulcerations, amputations and discolored scale-like skin. While a relatively new phenomenon, krokodil use is prevalent in Russia and the Ukraine, with at least 100,000 and around 20,000 people respectively estimated to have injected the drug in 2011. In this paper we review the existing information on the production and use of krokodil, within the context of the region's recent social history. METHODS: We searched PubMed, Google Advanced Search, Google Scholar, YouTube and the media search engine www.Mool.com for peer reviewed or media reports, grey literature and video reports. Survey data from HIV prevention and treatment NGOs was consulted, as well as regional experts and NGO representatives. FINDINGS: Krokodil production emerged in an atypical homemade drug production and injecting risk environment that predates the fall of communism. Made from codeine, the active ingredient is reportedly desomorphine, but - given the rudimentary 'laboratory' conditions - the solution injected may include various opioid alkaloids as well as high concentrations of processing chemicals, responsible for the localized and systemic injuries reported here. Links between health care and law enforcement, stigma and maltreatment by medical providers are likely to thwart users seeking timely medical help. CONCLUSION: A comprehensive response to the emergence of krokodil and associated harms should focus both on the substance itself and its rudimentary production methods, as well as on its micro and macro risk environments - that of the on-going syndemic of drug injecting, HIV, HCV, TB and STIs in the region and the recent upheaval in local and international heroin supply. The feasibility of harm reduction strategies for people who inject krokodil may depend more on political will than on the practical implementation of interventions. The legal status of opioid substitution treatment in Russia is a point in case.