Objective To investigate the genotoxicity of aniline and repair dynamics in hepatocytes and lymph-cytes.Methods Aniline was administered intragastrically to SPF Kunming mice ( five mice in each group) in a single dose of 100 mg/kg body weight.The hepatocytes and peripheral blood lymphocytes were obtained at 3, 8, 16, 24, and 32 hours after aniline administration, respectively.The control mice received tap water only.The DNA damages were detected by single cell gel electrophoresis assay ( SCGE) and the time-effect relationship was analyzed.Results The results of SCGE experiment showed that both the tail lenth and tail moment of the hepatocyte DNA were increased gradually from 8 h, and reached the maximum at 16 h ( P<0.01) after aniline administration.As time went on, DNA damage was recovered gradually, and the two DNA damage indexes were completely returned to control levels at 32 h after aniline administration (P>0.05).The two DNA damage indexes of peripheral blood lymphocytes started to increase at 16 h, reached the maxi-mum at 24 h ( P<0.01) , and began to recover at 32 h after aniline administration.Conclusions Our findings suggeste that aniline may be a potential genotoxicant to hepatocytes and peripheral blood lymphocytes.There is a clear time-response relationship in terms of the two DNA damage indexes, indicating that hepatocytes and lymphocytes in mice possess an effi-cient DNA repair mechanism against aniline toxicity.