Objective:To test the in vitro protective role of aqueous extract of Ocimum gratissimum Linn. (0.gratissimum) and ascorbic acid against nicotine-induced murine peritoneal macrophage. Methods:Peritoneal macrophages from mice were treated with nicotine(10 mM),nicotine (10 mM) with aqueous extract of O.gratissimum(1 to 25μg/mL),and nicotine(10 mM) with ascorbic acid(0.01 mM) for 12 h in cell culture media,while the control group was treated with culture media.Levels of free radical generation,lipid peroxidation,protein carbonyls,oxidized glutathione levels and DNA damage were observed and compared.Results:Phytochemical analysis of aqueous extract has shown high amount of phenolics and flavonoids compound present in it.The significantly increased free radical generation,lipid peroxidation,protein carbonyls,oxidized glutathione levels and DNA damage were observed in nicotine-treated group as compared to the control group:those were significantly reduced in aqueous extract of O. gratissimum and ascorbic acid supplemented groups.Moreover,significantly reduced antioxidant status in nicotine exposed murine peritoneal macrophage was effectively ameliorated by these two products.Among the different concentration of aqueous extract of O.gratissimum,the maximum protective effect was observed at 10μg/mL which does not produce any significant change in the normal cell.Conclusions:These findings suggest the potential use and beneficial role of O.gratissimum as a modulator of nicotine-induced cellular damage in murine peritoneal macrophage. Objective: To test the in vitro protective role of aqueous extract of Ocimum gratissimum Linn. (0. gratissimum) and ascorbic acid against nicotine-induced murine peritoneal macrophage. Methods: Peritoneal macrophages from mice were treated with nicotine (10 mM), nicotine 10 mM) with aqueous extract of O.gratissimum (1 to 25 μg / mL) and nicotine (10 mM) with ascorbic acid (0.01 mM) for 12 h in cell culture media, while the control group was treated with culture media. Levels of free radical generation, lipid peroxidation, protein carbonyls, oxidized glutathione levels and DNA damage were observed and compared. Results: Phytochemical analysis of aqueous extract has shown high amount of phenolics and flavonoids compound present in it. peroxidation, protein carbonyls, oxidized glutathione levels and DNA damage were observed in nicotine-treated group as compared to the control group: those were significantly reduced in aqueous extract of O. gratissimum and ascorbic acid supplemented groups. More than antioxidant potential in nicotine exposed murine peritoneal macrophage was effectively ameliorated by these two products. Among the different concentration of aqueous extract of O.gratissimum, the maximum protective effect was observed at 10 μg / mL which does Not produce any significant change in the normal cell. Conclusions: These findings suggest the potential use and profitable role of O.gratissimum as a modulator of nicotine-induced cellular damage in murine peritoneal macrophage.