Objectives: The aim was to demonstrate the equivalent efficacy of intranasal estradiol (Aerodiol(R) Servier, Istanbul, Turkey) 300 mg/day relative to a standard oral estradiol therapy of 2 mg/day and to assess the therapeutic value of the potential benefits of Aerodiol(R. Methods: Two hundred and one postmenopausal women with severe menopausal symptoms were recruited to the trial. Women received either intranasal Aerodiol(R) 300 mug/day (one spray delivery of 150 mug per nostril) or an oral estradiol 2 mg for 24 weeks. Severity of symptoms were compared based on the Kupperman index (KI) at the end of 24 weeks. Results: The KI score decreased markedly in both groups between W0 and W24. At W24, the two treatments were shown to be statistically equivalent (P<0.001). The incidence of adverse events was very similar in both groups; those related to treatment were of mild or moderate intensity in 95% of cases for the nasal group and 90% for the oral group. Conclusions: In conclusion, pulsed estrogen therapy using Aerodiol(R) is safe, easily used and highly efficient in alleviating postmenopausal symptoms with a dose of 300 jig. The dose of 300 μg in one administration per day offers the optimal therapy whilst being easily adaptable to each patient's clinical response. (C) 2002 International Federation of Gynecology and Obstetrics. Published by Elsevier Science Ireland Ltd. All rights reserved.