Genotoxic activity of the aminophenols as evidenced by the induction of sister chromatid exchanges

1 Most hair dyes contain the structural isomers ortho-, meta- and para- aminophenol which were investigated concerning their ability to induce sister chromatid exchanges (SCE) in cultured human lymphocytes in vitro and in Chinese hamster bone marrow cells in vivo. 2 In vitro only ortho-aminophenol significantly induced SCE in a dose-dependent manner. 3 In vivo none of the structural isomers increased significantly the SCE frequency. 4 It is concluded that ortho-aminophenol is a weak directly acting compound which is detoxified during its metabolism.