The whole-blood kinetics of chloroquine and desethylchloroquine were studied in five healthy Ghanaian subjects. Chloroquine was rapidly absorbed, and peak concentrations were reached within 2 h. The drug disappeared from blood in a multiexponential manner, and the mean terminal half-life from day 7 to day 28 was 13 days. Desethylchloroquine concentrations were generally higher than those of chloroquine after 48 h. Renal clearance accounted for 65% of the apparent total clearance of chloroquine. The estimated mean total urinary recovery of the drug and its desethyl metabolite was 80% of the dose. Whole-blood concentrations of chloroquine offer some advantages compared with plasma concentrations, as this drug concentrates in the formed elements, and special precautions must be taken to obtain representative plasma concentrations.