The discovery and development of the artemisinin class of antimalarial drugs is one of the great recent success stories of global health. However, after at least two decades of successful use, resistance has finally emerged and appears to be spreading rapidly throughout South-East Asia in spite of our best efforts at containment. If this were also to occur in Africa, it would have disastrous implications for the continent subject to the world's greatest burden of Plasmodium falciparum. The earliest indications of incipient artemisinin resistance may be a slowing of the rate at which parasites are cleared from the blood following treatment. The Worldwide Antimalarial Resistance Network have analysed data from 29,493 patients from 84 clinical trials in order to define the nature and determinants of early parasite clearance following artemisinin-based treatment in African populations. In doing so, they lay the foundation for systems intended to enable the earliest possible detection of emerging artemisinin resistance in Africa. Please see related article: http://www.biomedcentral.com/1741-7015/13/212.