Abstract
Human breast secretions, as obtained by nipple aspiration, were analysed for the presence of mutagenic activity by means of the Ames test. The overall incidence of women with secretions giving positive tests against Salmonella typhimurium, either strain TA98 or TA100, was 7.64%. No significant association was identified between the incidence of mutagen-positive breast secretions and age, menopausal status or the presence of breast abnormality in these women. Furthermore, there was no obvious environmental characteristic common to women with mutagen-positive fluids.