[en] Several phytoceuticals and extracts of medicinal plants are reported to mitigate deleterious effects of ionizing radiation. The potential of hydro-alcoholic extract of Clerodendron infortunatum (CIE) was investigated for providing protection to mice exposed to gamma radiation. Oral administration of CIE bestowed survival advantage to mice exposed to lethal doses of gamma-radiation. The radiation - induced depletion of total blood count and bone marrow cellularity were prevented by treatment with CIE. The damage to cellular DNA, as evidenced from comet assay, and micronucleus index was also found to be decreased upon CIE administration. Radiation induced damages to intestinal crypt cells was also reduced by CIE. Studies on gene expression in intestinal cells revealed that there was a marked increase in bax/bcl-2 ratio in mice exposed to whole body 4 Gy gamma radiation and administration of CIE resulted in significant lowering of this ratio, suggestive of reduction of radiation induced apoptosis. Levels of expression of the DNA repair gene, atm was found to be elevated along with a reduction in the inflammatory cox-2 following CIE treatment in the intestinal tissue of irradiated animals. Thus the results suggest the beneficial use of Clerodendron infortunatum for mitigating radiation toxicity. (author)