A differential pulse polarographic method for the determination of trace amounts of selenium contained in Chinese herbal drugs is described. In the Na(2) SO(3)KIO(3)NH(3)NH(4)Cl Medium (pH > 9) the selenium complex Se(O)SO(2-)(3) gives a catalytic wave, the peak potential of the wave is -0.76 V vs. Ag/AgClKCl (1M), and the peak current is directly proportional to selenium in the range 0.01-1.0 mug per 0.5 g of sample (0.08-8 ng/ml). The recoveries of selenium added to the samples tested are between 95 and 105%. The method is simple, sensitive, accurate and rapid. The results are in good agreement with those found by a DAN (2,3-diamino-naphthalene) spectrofluorimetric method.