There are variations in the radiation response of lipid peroxidation (LPO) indices. The initial rise of spontaneous chemiluminescence (SCL) immediately after whole-body irradiation (8 Gy) is followed by its rapid drop below the initial level. A considerable increase of the LPO level in the blood, spleen and thymus occurs 24 hr or 2 days after irradiation. The decrease on day 7 is followed by the increase on day 14. The periods of LPO inhibition (15 to 60 min and 7 days after irradiation) correspond to two waves of the hypersecretion of catecholamines and glucocorticoids that have antioxidant activity. With local irradiation of rat skin (a single exposure to 50 Gy) the SCL and malondialdehyde intensity peaks in blood serum are the same as those observed after whole-body irradiation, whereas in the spleen and thymus, these indices regularly decrease. There are peculiarities in the dynamics of triboluminescence in rat blood and organs that is attributed, in addition to LPO, to the effect of radiation on the electric parameters of tissues.