This document discusses principles of quality control for registered medicines, non-registered medicines, and counterfeits. It provides background on the EDQM and regulatory frameworks for quality control of registered medicines. For non-registered medicines, it notes the lack of standardized testing methods and importance of developing recognized standards given their traditional origins and limited data. The document also defines counterfeited medicines as illegal and discusses basic areas targeted, including blockbuster and expensive drugs, as well as how, when, and where counterfeiting occurs. It emphasizes the importance of representative sampling and specialized expertise in quality control testing.