The use of oestrogens in the longer term is an area of considerable current scientific and clinical debate. The extra-reproductive range of oestrogen actions is broad, with these steroid hormones and their receptors (ERs) being intimately involved in the normal function of, inter alia, the adult female skeleton, the cardiovascular system and the brain. Desirable as the restoration of normal circulating oestrogen may be after menopause, HRT use is compromised by the engagement of the reproductive sites of breast and uterus. This may cause concern to patient and physician alike due to the consequent imposition of cyclical bleeding and risk of breast malignancy. In the individual patient, therefore, a balance of risk against benefit has to be struck so that the patient may be precisely advised of the type and duration of oestrogen replacement which may be indicated in her own case. The advent of selective oestrogen receptor modulation with its ability to delete adverse effects in breast and endometrium, is a substantial pharmacological and clinical advance.