Exposure to ionizing radiation can cause severe skin damage, leading to the development of cutaneous radiation syndrome. Wound healing of radiation-induced skin injuries proceeds in defined phases that depend on the intensity and type of radiation exposure. Skin damage caused by ionizing radiation can occur not only through accidental exposure, as in the case of the Chernobyl disaster, but also during radiotherapy of tumor patients. The extent of cell damage by ionizing radiation is greater in the presence of oxygen (“oxygen-effect”), most likely by the generation of reactive oxygen species (ROS), which cause damage to macromolecules (nucleic acids, proteins, lipoproteins, and polymeric carbohydrate compounds). If DNA lesions are not repaired, cells can die by apoptosis. This chapter describes the application of sensitive high-throughput microplate assays to determine the frequency of single- and double-strand DNA breaks in individuals exposed during cleanup work at the Chernobyl reactor (“liquidators”), in personnel who had worked in the destroyed Unit IV of the reactor, and in radiotherapy patients. In addition, new materials based on chitin-glucan-melanin complexes (ChGMC) and melanin-glucan complexes (MGC) or on the regeneratively active polymer inorganic polyphosphate (polyP) are presented to prevent the induction and accelerate the healing of radiation-induced skin damage.