Climacteric symptoms in 120 women were treated with a total of 469 hormone implants (oestradiol 50 mg and testosterone 100 mg) over a period of four years. All patients with a uterus were given an oral progestogen to prevent endometrial hyperplasia. There was a marked response to treatment, hot flushes being improved in all patients, depression in 99% and loss of libido in 92%. Patient acceptability of this type of treatment was good and there were few side effects or complications. After therapy, the serum oestradiol exceeded the serum oestrone but remained within normal limits. When climacteric symptoms returned and re-implantation occurred the serum levels of oestrone, oestradiol, luteinising hormone (LH), follicle stimulating hormone (FSH) and testosterone were within the normal range for the reproductive age. This indicates that the return of symptoms is due to a change in the hormone levels rather than absolute hypo- oestrogenism .