The changes of gelsolin in irradiated cells and its effects on oxidative injury of irradiated mice were investigated. The relative expression levels of cGSN in cultured human intestinal epithelial cells (HIEC) irradiated by ,137,Cs γ-rays with 8 Gy and 12 Gy were detected by western blot assay. BALB/c mice were divided randomly into gelsolin group treated with gelsolin, irradiated group and normal control group. Then the contents of plasma malonaldehyde (MDA), superoxide dismutase (SOD) and whole blood glutathione (GSH) were examined at 2 d and 7 d after irradiation of 6 Gy γ-rays. The relative level of cGSN in HIEC exposed to 8 Gy was lower than that of the normal level from 2 to 12 h post-radiation (the difference between post-irradiation observed at 12 h and normal level was significant,p,<,0.05), but higher than that of the normal level observed at 24 h post-radiation. The level of cGSN in HIEC exposed with 12 Gy was also lower than that of normal level determined at 2 h post-radiation but higher than that of the normal level from 4 to 24 h post-radiation. (The differences at 6 and 12 h time points comparing to the normal level were statistical significant respectively,p,<,0.05). Plasma levels of GSH and SOD in gelsolin treated mice after exposure to 6 Gy irradiation were obviously higher than that of irradiation treated groups at 2 and 7 d (,p,<,0.05), whereas MDA level was significantly lower than that of only irradiation treated groups (,p,<,0.05). Gelsolin might be able to protect mice against oxidative injury induced by radiation.