This briefing paper, aimed at policymakers and researchers, discusses the regulatory implications of having varied definitions of the term 'counterfeit' and outlines successful law enforcement initiatives to halt the trade in fake drugs. The paper outlines the problem of counterfeit medicines and the urgent issues to be considered by the international community before taking additional steps to tackle it. It discusses the controversy around intellectual property rights and counterfeits, and investigates the motives behind some anti-counterfeiting initiatives that seem to be more concerned with protecting patents.