A survey of 60 women who had undergone simple hysterectomy with preservation of ovaries revealed a high prevalence of menopausal flushes. Only 5 (8%) had menopausal concentrations of gonadotropins and estradiol. This is similar to the prevalence of natural menopause in population of comparable age. Of the remaining 55 women, 28 (47% of the total) had normal gonadotrophins and estradiol concentrations although they complained of hot flushes; these levels were not significantly different from those in 27 women who did not flush. The "flushers" did, however, have significantly diminished bone mineral index and higher serum uric acid concentrations than the "non-flushers". Flushes disappeared in those women who took estrogen replacement therapy. These data show that although full-blown menopause does not increase in frequency following simple hysterectomy, a subtle diminution in estrogenisation is frequent. This hypo-estrogenisation is sufficient to cause: (a) hot flushes; (b) demineralisation of the skeleton and (c) an elevation in serum uric acid concentrations. There may be a case for estrogen therapy in all women who develop hot flushes following simple hysterectomy.