The radioprotective potential of alcoholic extract of root of R. cordifolia, was studied by survival, hemopoietic cell protection and micronucleus assay. The LD50 value for the alcoholic root extract was found to be 1200 mg/kg body weight at 72 hr post irradiation. A significant radiation protection (67%) as assessed by increased animal survival was observed when R. cordifolia (RC) extract was administered intraperitoneally, 90 min. before the radiation exposure. Besides, the extract also inhibited radiation induced lipid peroxidation measured by the inhibition of thiobarbituric acid reactive substance (TBARS). The RC extract at a selected dose of 460 mg/kg body weight was effective in protecting the radiation induced suppression of endogenous colony forming units in spleen. A significant inhibition of radiation (2 Gy) induced micronuclei formation was observed when RC extract was administered 90 min prior to irradiation. Thus, it appears that the alcoholic root extract of R. cordifolia provides significant protection against radiation induced lipid peroxidation, hemopoietic injury and genotoxicity. The mechanism of action of RC extract appears to be through its anti-oxidant, metal chelation and anti-inflammatory property.