- The radiobiological response of CHO-K1 cells treated with ethanol is described. Both radioprotective and radiosensitising effects were found, depending on the duration of exposure before irradiation and the number of cells exposed. In spite of effects of ethanol on the shoulder of the primary survival curve, split-dose recovery was not affected. The radiobiological effect of alcohols is normally attributed either to radical scavenging or to oxidation. The findings presented here do not support either of these mechanisms.