There are number of methods used for detection of antioxidant activities. We have developed a new method using a compound (resazurin) which undergoes a visible colour shift by chemical or physical interaction with ascorbate and other antioxidant compounds. This novel method was developed to measure the antioxidant activity using the resazurin dye in microtitre- plate. The experiment protocol, which is rapid and inexpensive, ensures sensitivity and reproducibility in the measure of antioxidant activity of hydrophilic or water soluble antioxidant compounds. This method is able to achieve more accuracy in the determination of the minimum antioxidant concentration (MAC) values of natural products, including crude extract, chromatographic fractions or purified compounds comparing with ascorbic acid and other standard antioxidant. Therefore, in our opinion this procedure can quickly provide useful information on the antioxidant contents of foods and plants extracts using a very small sample quantity.