Sister-chromatid exchanges (SCE) were examined in the peripheral lymphocytes of 52 Korean women living in the vicinity of an industrial complex. They were generally non-smokers ranging from 22 to 56 years of age. The mean SCE score of the volunteers was 6.01 +/- 0.15 (SE). Only coffee intake produced a significant increase of SCE by comparison with the mean SCE for those that did not take coffee. Other parameters, including alcohol intake, working in industry and the presence of hepatitis B surface antigen (HBsAg), did not produce an increase in SCE. There was no effect on SCE due to age.