Total antioxidant activities for several popular vegetables and traditional Chinese herbs were evaluated in an ABTS/H2O2/HRP system with a microplate reader. This improved method offers a rapid and sensitive way to measure total antioxidant activity of testing samples. Most samples had antioxidative capacities. Among the tested vegetables, sugar beet and red cabbage had the highest total antioxidant activity, whereas tropical Almond Terminalia and Moutan Radicis Cortex had exceptionally high total antioxidant activity in the tested Chinese herbs.