Reactive oxygen radicals play an important role in carcinogenesis and other human disease states. Antioxidants with present in consumable vegetables have received considerable attention as cancer chemopreventive agents. Thus, in order to identify antioxidants in plant extracts, test materials were assessed for potential to scavenge stable 1, 2 diphenyl-2-picrylhydrazyl (DPPH) free radicals. Approximately 13 indigenous plant extracts were evaluated, and all of them were found to be actived in the DPPH free radical scavenging assay by using ascorbic acid as a reference. Based on this assay, the extracts exert their radical scavenging activity in a dose-dependent manner. The results of this study showed an interesting data, indigenous vegetable plants showed an inhibitory effect on free radical. Especially, antioxidant potencies of Solanum trilobatun Linn. and Jussiaea repens Linn. are higher and upper range of those potent antioxidant and ascorbic acid. The mechanism of free radical inhibition of these plants may be due to radical scavenging. Hence, these indigenous plants seem to be contained compounds which might prevent many harmful processes in the body. However, its possible mechanism should be further investigated.