Variability in the severity of asthma during various phases of the menstrual cycle has been frequently suspected. However, the hormonal changes that might affect mediators of bronchospasm have yet to be elucidated. The case of a 41-year-old woman suffering from longstanding asthma with life-threatening exacerbations is reported. The patient was treated with buserelin, a gonadotropin releasing hormone (GnRH) analogue, which created a temporary chemical menopause and thus permitted diagnosis of a premenstrual exacerbation of asthma and offered insight into potential therapy. GnRH analogues may therefore be of value in assessing women with severe asthma suspected to vary with the menstrual cycle. The addition of estrogens and progestins at the same time as treatment with GnRH analogue may be of value in determining the role of these hormones in the pathogenesis of menstrually related exacerbations of asthma.