At each visit and in the morning on day 3, the child will be examined, the mother asked for any symptoms and signs of side-effects, the temperature measured. Furthermore, a blood sample will be taken for examination of malaria parasites. On day 0 samples for measurement of antimalarial drugs and for genotyping of the parasites will be taken on filterpaper. In a subgroup of 50 children a blood sample for in vitro culturing and for analysis of the number of leucocytes will also be taken.