In this study, the antioxidant activity of 50% aqueous methanol extracts of 38 plants growing in the Afyonkarahisar province of Turkey were evaluated by various antioxidant assay, including free radical scavenging, hydrogen peroxide (H2O2) scavenging and metal (Fe2+) chelating activities. The methanolic fruit extracts of the Cornus and Morus species (H2O2 and DPPH scavenging activities, Fe2+ chelating activity) and the methanolic leaf extracts of the Mentha species (DPPH scavenging activities) examined in the assay showed the strongest activities. These antioxidant properties depended on the concentration of samples.