The central hypothesis of the project is that the different half-lives of the active substances used in artemisinin-based combination treatments have a direct impact on the frequency of subsequent malaria episodes. The detailed comparative analysis of this relationship between pharmacokinetics and parasitological impact is the focus of this project. The aims of the project are defined as follows: 1. The extensive and growing data set makes it possible for the first time to address the important question of whether certain combinations of active substances actually suppress subsequent malaria episodes (as previously assumed) or merely delay them. 2. The relationship between the observed accumulation of desethylamodiaquine or lumefantrine and the haematological and clinical parameters recorded in the study protocol will be investigated with regard to potential impacts on tolerability. A complete data set from the clinical trial in Mali, Burkina Faso and Guinea is available for this purpose. 3. The complex liquid chromatography-mass spectrometry (LC-MS) method of determining piperaquine and pyronaridine is being validated and applied to available samples. This will enable direct comparison of the data with desethylamodiaquine or with lumefantrine.