Nicotine, a pharmacologically active component of cigarettes smoke causes devastating effects in important biomolecules of the cell through generation of free radicals leading to genomic instability. Bacopa monniera is a reputed drug in Ayurveda known for its hepatoprotective and DNA protective effects. In this study, an aqueous extract of Bacopa monniera (BAE, 50 mg/kg i.p.) was investigated for its ability to reduce nicotine-induced lipid peroxidation (LPO) and confer genoprotection in Swiss mice. Genoprotective effect was assayed using micronucleus (MN) assay. LPO status was studied by evaluating MDA levels and antioxidant status. Nicotine altered hepatic function as evident by increased ALP and GST levels and decreased SOD, catalase and GPx activities. BAE treatment restored antioxidant enzymes such as SOD, catalase and GPx in liver. BAE treatment also significantly reduced the frequency of micronuclei induced by nicotine by decreasing the incidence of micronucleated polychromatic erythrocytes (MN-PCE). Hepatic GSH, ALP and GST levels were brought to normal values indicating protection. The results of the present study suggest that BAE exerts protective effects by modulating the extent of lipid peroxidation and enhancing the antioxidant status. Copyright © 2007 John Wiley & Sons, Ltd.