Oxidative stress is one of the major causes of degenerative conditions occurring at cellular level with serious health implications. This study was aimed at investigating the antioxidative potentials of probiotic lactobacilli of Indian gut origin and their ability to augment antioxidant defense enzyme systems in the host cells under oxidative stress conditions. A total of 39 Lactobacillus cultures were assessed for their resistance against reactive oxygen species. Most of the cultures were moderately to strongly resistant towards 0.4 mM H(2)O(2). The Lactobacillus isolate CH4 was the most H(2)O(2) resistant culture with only 0.06 log cycle reduction. Majority of the cultures demonstrated high resistance towards hydroxyl ions and Lp21 was the most resistant with log count reduction of 0.20 fold only. Almost all the cultures were also quite resistant to superoxide anions. Lp21 also showed the highest superoxide dismutase content (0.8971 U). Amongst the 39 cultures, Lactobacillus spp. S3 showed the highest total antioxidative activity of 77.85 ± 0.13 % followed by Lp55 (56.1 ± 1.2 %) in terms of per cent inhibition of linolenic acid oxidation. Lp9 up-regulated the expression of superoxide dismutase 2 gene in HT-29 cells both at 0.1 mM (1.997 folds) and 1.0 mM H(2)O(2) (2.058 folds) concentrations. In case of glutathione peroxidase-1, Lp9, Lp91 and Lp55 showed significant (P < 0.001) up-regulation in the gene expression to the level of 5.451, 8.706 and 10.083 folds, respectively when HT-29 was challenged with 0.1 mM H(2)O(2). The expression of catalase gene was also significantly up-regulated by all the cultures at 0.1 mM H(2)O(2) conditions. It can be concluded that the antioxidative efficacy of the putative probiotic lactobacilli varied considerably between species and strains and the potential strains can be explored as prospective antioxidants to manage oxidative stress induced diseases.