The pharmacokinetics of quinine were studied in seven normal African children and in six African children suffering from kwashiorkor, after an oral dose of 10 mg kg-1 of quinine hydrochloride. The two groups were similar in age but the children with kwashiorkor weighed significantly less than the control children (P less than 0.001). The children with kwashiorkor further differed from the control children in having significantly lower packed cell volume (P less than 0.001), total plasma protein and plasma albumin (P less than 0.001), and higher serum SGOT (P less than 0.05). The apparent absorption half-life was significantly longer in kwashiorkor than in controls (P less than 0.05). Similarly, the Cmax was significantly lower (P less than 0.01) in kwashiorkor than in controls. Quinine was eliminated more slowly in children with kwashiorkor, the elimination half-life being significantly longer (P less than 0.001) and the oral clearance significantly less (P less than 0.001) than in controls. It is concluded that kwashiorkor significantly affects the pharmacokinetics of quinine, and that the effect may be due to the pathological changes in the intestine and liver in this condition.