According to previous studies, phytochemicals have many pharmacological activities. Chinese herbal remedies that have potential use in many diseases. Caffeic acid, p-coumaric acid, oleanolic acid and ursolic acid are bioactive compounds from plants. In the present study, the antioxidant properties of the caffeic acid, p-coumaric acid, oleanolic acid and ursolic acid were evaluated by using different in vitro antioxidant assays such as 1, 1-diphenyl-2-picryl-hydrazyl free radical (DPPH•) scavenging, metal chelating activities and cytochrome c reduced method. The result of this study showed that caffeic acid, p-coumaric acid, oleanolic acid and ursolic acid all have apparent antioxidant activity by these assays. Among these compounds, oleanolic acid was capable of inhibiting xanthine oxidase and showed a significant antioxidant effect. Thus, these compounds have potential to be used as natural antioxidants against oxidative deprivation for preventing carcinogenesis and other diseases.