Hormone replacement therapy aims to replace oestrogen in the postmenopausal woman and so reverse the adverse effects of oestrogen lack. The aims therefore, are quite different to those of contraception for which high dose artificial steroids are used in order to suppress ovulation. HRT uses more "natural" steroids and in lower doses.

In women who have not had a hysterectomy, a progestogen must be included to avert the consequences of prolonged exposure to unopposed oestrogen.

HRT has dramatic therapeutic effects but a few side effects which must be borne in mind if prescribing. However, in most cases, advantages far outweigh disadvantages, and it's prescription should not be irrationally avoided.