The importance of drug concentrations, nutritional status and other host factors were explored in uncomplicated falciparum malaria therapy with fixed-dose chloroquine+sulfadoxine/pyrimethamine (CQ+SP). A total of 83 children were treated. Younger children (6-24months) were given half-strength (HS) and older children (2-5years) full-strength (FS) CQ+SP as recommended. The concentrations of CQ and sulfadoxine (S) were determined by HPLC in 100μl of capillary blood on filter paper. Multiple logistic regressions were used to determine associations with outcomes. Stunting (height-for-age