Sister-chromatid exchanges before and after hair dyeing.

Sister-chromatid exchanges (SCE( in the peripheral lymphocytes of 13 women and 1 man were scored immediately before, 6 h after and 7 days after the application of a hair dye by a professional hairdresser under normal conditions. All the hair dyes used in this study gave positive results when tested in the Salmonella/microsome test for mutagenic activity. 6 volunteers showed increases and 8 showed decreases in mean numbers of SCE per cell 6 h after dyeing: 2 of these increases and 3 of the decreases wee statistically significant. when the mean SCE per cell of the who group were compared there were no significant difference between the pre-dyeing sample and the 2 samples taken 6 h or 7 days after dyeing. It was concluded that single applications of proprietary hair dyes cause no consistent increase in the SCE levels in the peripheral lymphocytes of the people taking part in this study.