Medicinal plants and their phytochemical constituents are considered as paramount entity to treat various human ailments. The present study was designed to investigate the effect of ethanolic extract of Hygrophila auriculata on mercury induced oxidative damage in rat liver. Mercuric chloride (HgCl2) (1mg/kg b.w, i.p) was administered three times in a week for two weeks to induce mercury toxicity. Mercury damage to the liver was evident from increase in the activities of marker enzymes such as alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and acid phosphatase (ACP) in serum. The level of lipid peroxidation (LPO) was increased in liver tissue with concomitant decrease in both the enzymic and non-enzymic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), vitamin C and vitamin E. The glutathione metabolizing enzymes viz., glutathione reductase (GR), glucose-6- phosphatase dehydrogenase (G6PD) and glutathione -S- transferase (GST) were also found to be decreased. Interestingly post treatment with ethanolic extract of Hygrophila auriculata (100 mg/kg b.w, p.o) for 10 days after mercury induction significantly ameliorated the mercury induced oxidative damage which is evidenced by the reduction in the marker enzymes, lipid peroxidation and increase in the antioxidant enzymes and glutathione metabolizing enzymes. Thus, this remarkable hepatoprotective activity of ethonolic extact of the plant could be due to the antioxidant nature, which scavenge excessive free radicals that were involved in the acceleration of per-oxidation reaction and the potent membrane protective property which ultimately render protection to the liver against HgCl2 induced oxidative damage.