Hydrogen peroxide (H 2 O 2 ), a major reactive oxygen species (ROS) produced during oxidative stress, is toxic to the cells. Hence, H 2 O 2 has been extensively used to study the effects of antioxidant and cytoprotective role of phytochemicals. In the present investigation H 2 O 2 was used to induce oxidative stress via ROS production within PC12 and L132 cells. Cytoprotective propensity of Bacopa monniera extract (BME) was confirmed by cell viability assays, ROS estimation, lipid peroxidation, mitochondria membrane potential assay, comet assay followed by gene expression studies of antioxidant enzymes in PC12 and L132 cells treated with H 2 O 2 for 24 h with or without BME pre-treatment. Our results elucidate that BME possesses radical scavenging activity by scavenging 2,2-diphenyl-1-picrylhydrazyl, 2,2 0 -azinobis(3-ethylbenzothiazoline-6-sulphonic acid), superoxide radical, and nitric oxide radicals. The IC 50 value of BME against these radicals was found to be 226.19, 15.17, 30.07, and 34.55 lg/ml, respectively). The IC 50 of BME against ROS, lipid peroxidation and protein carbonylation was found to be 1296.53, 753.22, and 589.04 lg/ml in brain and 1137.08, 1079.65, and 11101.25 lg/ml in lung tissues, respectively. Further cytoprotective potency of the BME ameliorated the mitochondrial and plasma membrane damage induced by H 2 O 2 as evidenced by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase leakage assays in both PC12 and L132 cells. H 2 O 2 induced cellular, nuclear and mitochondrial membrane damage was restored by BME pre-treatment. H 2 O 2 induced depleted antioxidant status was also replenished by BME pre-treatment. This was confirmed by spectrophotometric analysis, semi-quantitative RT-PCR and western blot studies. These results justify the traditional usage of BME based on its promising antioxidant and cytoprotective property.