Serum quinine concentrations were determined in 51 children with uncomplicated falciparum malaria and 22 controls. Quinine 10 mg salt/kg was given one-hour, two-hour, four-hour intravenously in group A (14 patients, 5 controls), group B (12 patients, 6 controls), Group C (10 patients, 6 controls) and given orally in group D (15 patients, 5 controls). In malaria patients, the highest serum quinine levels were observed at the end of intravenous infusion and by the 4th hour after oral medication. Mean of the peaks of the drug concentrations of the 4 schedules were not significantly different, ranging from 22 to 28 n mol/ml. Serum concentrations in the patients were significantly higher than those of the controls. The total clearance of quinine in the patients were approx. 1 ml/min/kg, which was significantly less than those of the controls. The total apparent volume of distribution of the drug was similarly reduced. In patients it was about 0.8 litre/kg. The elimination half times of quinine ranged from 9 to 11 hours, whereas the value in the controls ranged from 3 to 7 hours. Side effects of quinine were not observed.