An aglycone isolated from the fruits of T. chebula, triethylchebulate, significantly inhibited FeSO4 /Cys-induced microsomes lipid peroxidation and protected both H2O2- -induced RBCs hemolysis and RBCs auto-hemolysis in a dose-dependent manner. Furthermore, triethylchebulate demonstrated potent DPPH free-radical scavenging ability and moderately suppressed azide-induced mitochondria ROS formation. The results demonstrated that triethylchebulate was a strong antioxidant and free-radical scavenger, which might contribute to the anti-oxidative ability of T. chebula