Pre-treatment with α, β unsaturated aryl sulfones protects normal cells from the toxic side effects of ionizing radiation. Administration of a radioprotective α, β unsaturated aryl sulfone compound to a patient prior to anticancer radiotherapy reduces the cytotoxic side effects of the radiation on normal cells. The radioprotective effect of the α, β unsaturated aryl sulfone allows the clinician to safely increase the dosage of anticancer radiation. In some instances, amelioration of toxicity following inadvertent radiation exposure may be mitigated with administration of α, β unsatured arylsulfone.