OBJECTIVES: To analyze real occurrences of drug shortages throughout 2010 and 2012 and the underlying reasons. METHODS: We conducted a systematic search in the scientific literature, media and public domain on occurrences of drug shortages and the perceived underlying reasons. The type of drug shortages were categorized and considered in context to their impact on access to medicines and healthcare system efficiency. RESULTS: While there were 20 publications of any type around this subject in Pubmed in 1995, the number increased with 34 in the year 2000, 70 in 2005, 99 in 2010, and 128 in 2011.  The publications have discussed the health consequences, workarounds, and the health consequences of the workarounds.  In February 2012, 110 drugs were listed on the FDA Web site, including at least 14 commonly used cancer chemotherapy drugs. Likewise, drug shortages are reported in many countries around the world including European countries such as Spain, France, UK, Russia, Portugal, Greece, or Rumania. Over the years, the reasons for drug shortages have changed from being predominantly caused by shortages in the active ingredients or insufficient distribution systems to currently often being the consequences of strong cost-containment measures or economic crisis. CONCLUSIONS: Drug shortages are increasingly observed over the last decade. Drug shortages can have multiple reasons and are currently often induced by economic or cost-containment reasons, and to misaligned incentives in the supply chain.