AIM: To study the stereoselectivity of phase Ⅱglucuronidation metabolism of side-chain propranolol in Chinese Hah population.METHODS: Sixteen adult Chinese Hah volunteers with an average age of 20 years were given a single oral dose of 20 mg racemic propranolol. Human urine at indicated time after administration was collected and S-(-)-propranolol glucuronide and R-(+)-propranolol glucuronide were determined simultaneously by using RP-HPLC.RESULTS: The mean values of kwere 0.19±0.04 h-1 and 0.28±0.06 h-1, of t1/2 3.56±0.73 h and 2.45±0.50 h, of Tmax 2.21±0.45 and 1.75±0.33 h, and of Xu0-24 5.65±0.98 and 2.95±0.62 μmoL for S-(-)- and R-(+)-propranolol glucuronide, respectively. The cumulative excretion percentages in urine of doses were 14.7±2.46% and 7.68±1.60% for S-(-)- and R-(+)-propranolol glucuronide,respectively. The results showed the elimination rate constant kof S-(-)-propranolol glucuronide was less than that of R-(+)-propranolol glucuronide; and the elimination half-life (t1/2), Tmax and the cumulative excretion amount (Xu0-24) of R-(+)-propranolol glucuronide were significantly less than that of S-(-)-propranolol glucuronide.CONCLUSION: The propranolol glucuronidation of the side-chain undergoes stereoselective excretion in Chinese Han population after an oral administration of racemic propranolol.