The clinical characteristics and the responses to oral 4-aminoquinoline therapy of 150 malarious children presenting consecutively were investigated in an endemic area. At presentation, the 75 children who subsequently developed pruritus were significantly older and had significantly higher body temperatures than the 75 children who did not develop pruritus. There were no other significant differences in clinical presentation between the two groups. In children with pruritus, there was no correlation between age, weight, presenting body temperature, duration of illness or presenting peripheral parasite density and duration of pruritus. Responses to oral antimalarial drugs were similar in both groups. There was no correlation between indices of therapeutic response and the duration of pruritus. Analysis of the disposition kinetics of parasitaemia and of the hepatomegaly associated with malaria, using a non-compartmental model similar to that used in characterizing drug disposition, showed that the two groups had similar half-lives of parasitaemia (t(1/2 pd)), volumes of blood completely cleared of parasites per unit time (CL(Bpd)) and ratios of parasite-clearance time to t(1/2 pd), and similar values for the corresponding parameters derived from hepatomegaly resolution. There was no apparent relationship between the indices of parasite- or hepatomegaly-disposition kinetics and the duration of pruritus.