Knowledge of the antioxidant capacity of specific chemicals is essential to understanding the susceptibility to oxidative stress. Various assays have been developed for measuring the scavenging capacity of molecules. In the present study we used a continuous flow system for monitoring chemiluminescence (CL) reactions initiated by superoxide (O-2(-.)) (derived from xanthine-xanthine oxidase reaction), hydrogen peroxide (H2O2), hypochlorite anion (-OCl) (derived from NaOCl), hydroxyl ((OH)-O-.) (generated from O-2-FeSO4-buffer), or peroxynitrite (ONOO-) (freshly synthesized). By adapting the flow injection analysis (FIA) method, inhibition of luminol-CL responses of these reactive oxygen species (ROS) by ascorbic acid (well-characterized, chain-breaking antioxidant) and other antioxidants were also investigated. Data showed that to monitor the antioxidant sensitivity of CL responses initiated by ROS is possible by using FIA method.