Free radicals react with biological molecules and destroy the structure of cells, which eventually causes free-radical induced disease such as cancer, renal failure, aging, etc. In this study, 6 extracts and 4 pure compounds of Terminalia chebula RETZ. were investigated for anti-lipid peroxidation, anti-superoxide radical formation and free radical scavenging activities. The superoxide radical scavenging of the 4 pure compounds was further evaluated using electron spin resonance (ESR) spectrometry. The results showed that all tested extracts and pure compounds of T. chebula exhibited antioxidant activity at different magnitudes of potency. The antioxidant activity of each pure compound was derived from different pathways and was suggested to be specific.