Effect of 2.0 Gy gamma-dose delivered to rats in utero on 17th day of gestation was studied to monitor the radiation induced retardation of neurophysiological development in postnatal young ones. Rhizome of Podophyllum hexandrum which has been well documented for mitigating radiation injuries in adult mice was attempted for modifying radiation damage. Rats were observed from postnatal day 1 to 25 for the age of the appearance of physiological markers (pinna detachment, inscisor's eruption, eye opening) and acquisition of reflexes (surface righting, visual placing, reflex suspension, negative geotaxis). In irradiated groups there was a significant weight reduction in mother rats and offsprings throughout the experimental period. There was radiation-induced delay in the appearance of pinna detachment but not in eye opening and inscisor's eruption. Appearance of the reflexes were also delayed due to irradiation. Preirradiation administration of the extract of Podophyllum hexandrum (i.p., 200 mg/kg/b.w.) mitigated radiation induced postnatal physiological alterations. These studies have implications in protection against damage (in utero) due to planned radiation exposure.