Inositol hexaphosphate (IP-6) is a polyphosphorylated carbohydrate with potent antioxidant activity to prevent active oxygen species-mediated mutagenesis, cell injury and carcinogenesis. IP-6 also activates DNA repair mechanisms. Sublethal radiation causes DNA damage through the formation of free radicals, reactive oxygen species, and pyrimidine crosslinks leading to cellular proliferation, cell cycle arrest and apoptosis. In the skin it results in the induction of skin cancer, premature skin aging, immuno-suppression, inflammation, and cell death. Likewise sublethal exposure to ionizing radiation as in nuclear blasts (war-time, accidental, terrorist-induced etc), cosmic radiation, etc. also causes the same spectrum of damage to the cells and the organisms with acute symptoms and eventual high risk of many cancers. IP-6 and/or inositol and their pharmaceutically acceptable salts and derivatives, including pyrophosphates and citrate derivatives, significantly counteract the harmful effects of radiation, affecting cell cycle progression in a protective manner (more cells in the protective GI phase) as well as decreasing apoptosis and caspase-3 activation. Various salts of IP-6 are used with comparable efficacy and the combination of IP-6+inositol affords the best protection against radiation-induced cell injury. Thus IP-6 and inositol are effective agents for protection against nuclear, solar and other radiation injuries.