Dielectric spectroscopy and UV–Vis absorption spectroscopy techniques were carried out to investigate the radioprotective effects of antioxidant vitamins C and E on rats exposed to 2 Gy whole-body gamma irradiation (137 Cesium source). The rats were divided into four main groups: a control group, rats treated with vitamins C and E at a dose of 300 mg/kg once daily for five days until the day of irradiation, rats irradiated with 2 Gy, and finally rats pretreated with vitamins before irradiation. The dielectric properties of the whole blood, such as dielectric constant, dielectric loss, and AC conductivity, possessed a significant increase in the group of vitamins and a notable reduction in the irradiated group compared to the control. The rats pretreated with vitamins before irradiation indicated a remarkable augmentation compared to the irradiated group and a total recovery compared to the normal rats. Additionally, the absorption spectra of the hemoglobin molecules were measured in the range from 200 to 700 nm. The optical parameters, like characteristic peak position and intensity, full width at half maximum, molar absorption coefficient, and cross-sectional interaction, were calculated for each peak. All these parameters approximately possessed a slight increment in the group of animals treated with vitamins, while the irradiated animals indicated a considerable reduction compared to the control. The rats pretreated with vitamins before irradiation illustrated a partial recovery compared to the irradiated ones. The results illustrated an ameliorative effect of the antioxidant vitamins C and E delivered to animals before exposure to gamma radiation.