Bromocriptine 2-5 mg twice daily is effective in the treatment of both normoprolactinaemic and hyperprolactinaemic secondary amenorrhoea. This was demonstrated by the restoration of menstrual cycle and/or ovulation in 9 of 18 normoprolactinaemic and in 8 of 14 hyperprolactinaemic patients taking bromocriptine. Serum-prolactin level decreased in both groups of patients, and usually menstruation was recovered within 8 weeks'treatment. Galactorrhoea disappeared in 7 of 9 hyperprolactinaemic patients, and 2 became pregnant. After treatment had ceased spontaneous menstrual activity continued in 4 patients. 16 patients had side-effects the commonest being nausea and vertigo. These usually disappeared with the dosage was reduced, but 5 patients refused to continue. These results point to a new approach in the treatment of secondary amenorrhoea, even in those patients whose clinical findings give no indication of prolactin suppression.