The role of reactive oxygen species (ROS) in AFB1-induced cell injury was investigated using cultured rat hepatocytes. Malonaldehyde (MDA) generation and lactate dehydrogenase (LDH) release were determined as indices of lipid peroxidation and cell injury, respectively. Exposure to AFB1 for up to 72 h resulted in significantly elevated levels of LDH being released into the medium as well as the MDA generation in cultured hepatocytes. These effects were dose-dependent, indicating that AFB1 was capable of inducing oxidative damages in the cell. Further, MDA generation and LDH release were effectively inhibited by the addition of the following: (1) superoxide dismutase (500 units/ml), (2) catalase (1500 units/ml), (3) 10 mM desferrioxamine (a specific iron chelator), or (4) 260 mM dimethyl sulfoxide (a hydroxyl radical scavenger). These evidences therefore suggest that ROS, such as superoxide radicals, hydroxyl radicals and hydrogen peroxides, are involved in AFB1-induced cell injury in cultured rat hepatocytes.