Today, global access to quality medicines increasingly is threatened by many factors, including the presence of both substandard and counterfeit medicines. Substandard medicines1 can occur even when they are manufactured according to quality standards and Good Manufacturing Practices (GMPs). Counterfeit medicines2, on the other hand, which account for a larger percentage of poor quality medicines in resource-limited countries, occur because there is a deliberate intention to mislead. In both instances, however, the result is poor quality medicines that deny practitioners and patients of achieving expected health outcomes. Poor quality medicines can be especially burdensome in developing countries where they not only fail to produce needed results, but also absorb limited resources, undermine faith in already tenuous health systems, and may promote antimicrobial resistance to devastating infectious diseases such as HIV, malaria, and tuberculosis. Poor quality medicines represent a failure of standards and conformity assessments to standards, and such failures can and do arise at multiple points in the medicines continuum; from discovery, to development, to registration, through manufacturing and distribution, to utilization. The globalization of pharmaceutical markets has exacerbated this growing problem of poor quality drugs, particularly in countries that lack strong drug regulatory systems and oversight. Whatever standards and conformity assessments there are for medicine supply chains—from suppliers to manufacturers, and thereafter from practitioners to patients—these supply chains are becoming increasingly fragmented and fragile.