The pharmacokinetics of lithium was studied in 16 manic-depressive Chinese adults who were on lithium therapy in Hong Kong. A two-compartment open model was used to describe the plasma data obtained. The steady-state volume of distribution and total plasma clearance were estimated to be 63.4 +/- 38.3 L and 1.47 +/- 0.49 L/hr, respectively, which were similar to those reported in studies of Caucasian subjects. The lithium clearance was found to be significantly related to lean body mass (r = 0.646, p < 0.01) but not to either total body weight, age, or creatinine clearance. Interindividual variability in lithium clearance was substantially reduced to a coefficient of variation of 24.6% from 33.3% when lean body mass was considered. The combined plasma and urine data indicate that the rate and extent of lithium absorption were similar to those of earlier studies in Caucasian subjects on a standard lithium dosage.