Twelve health adults (6 M, 6 F) from the endemic area of Keshan disease and Kaschin-Beck's disease and 12 adults from nonaffected area were administered a single oral dose of 4 mg sodium selenite. Selenium in whole blood was determined by fluorescence spectrometry. Their basic levels of blood selenium were 64 +/- 16 and 220 +/- 20 ng.ml-1, respectively. The concentration-time data were treated by a computer with program 3P87, which revealed 2-compartment models with first order absorption and lag time. The pharmacokinetic parameters of low-Se group were T1/2g 1.8 +/- 0.6h, T1/2g 72 +/- 18 h, T1/2ka 3.2 +/- 1.8h, AUC 3,100 +/- 500 ng.h.ml-1, CL 32 +/- 7 ml.kg-1.h-1, Vc 1.45 +/- 0.19 L.kg-1, Tp 6.1 +/- 2.0 h, Cp 36 +/- 4 ng.ml-1, AUMC (S1) 130 +/- 26, VRT 174 +/- 17 h, MRT 55 +/- 4 h, and of normal-Se group were T1/2 3.4 +/- 0.7h, T1/2g 14 +/- 3 h. T1/2ka 2.3 +/- 0.6, AUC 1,420 +/- 210 ng.h.ml-1, Cl 57 +/- 7 ml.kg-1. h-1, Vc 0.54 +/- 0.09 L.kg-1, Tp 4.6 +/- 0.9h, Cp 75 +/- 5 ng.ml-1, AUMC (S1) 25 +/- 5, VRT 16 +/- 3 h, MRT 16.1 +/- 1.5 h.