Fifty-five depressed menopausal patients took part in a randomized double-blind cross-over trial using ;Harmogen' (piperazine oestrone sulphate) and placebo. The Beck depression inventory, hot flush counts, and patients' subjective assessment of well-being were used to assess clinical status. Hormonal, biochemical and coagulation profiles were carried out. Hot flushes improved significantly on oestrogen compared with placebo. Depression scores and well-being showed significant and equal improvement on oestrogen and placebo. Significant improvement in flushes in patients on placebo was observed in the first half of the trial but did not occur in the second half, in patients who had previously taken oestrogen. No significant changes occurred in biochemistry. Coagulation tests showed acceleration of the prothrombin time in patients taking ;Harmogen' compared with those on placebo. Piperazine oestrone sulphate is a relatively weak but safe oestrogen preparation, effective in treatment of vasomotor symptoms but no more effective than placebo in the treatment of depression.