[en] Lipid peroxides (LPO) in the tissues of mice was determined by the modified spectrophotometry with TBA. The results showed: 1) LPO contents in liver, spleen, kidney and bone marrow of mice dramatically increased and their proteins markedly reduced at the 15 the day after internal radiation. There exists negative relationship between them. 2) A gradual increase of LPO contents in liver, spleen and kidney of mice at the 72 th hour was followed by an increase of whole-body gamma radiation at a dose from 2 to 4 Gy. A linear relationship between the dose and LPO contents was observed in the dose range 0-4 Gy. 3) Tannic acid and squalene had certain anti-LPO effects