In a prospective study, seven patients with normal menstrual cycles were treated with pulsatile gonadotrophin-releasing hormone. They received one cycle of intravenous (i.v.) therapy and one cycle of subcutaneous (s.c.) therapy. Another four volunteers with normal cycles were treated for one s.c. cycle only. Cycles were compared to each other and to the normal unstimulated cycles of 14 other volunteers. Multiple follicular development could be achieved using both the i.v. and the s.c. routes. However, the i.v. route showed significantly higher luteinizing hormone (LH) and luteal steroid levels. Comparing s.c. cycles to controls, significantly lower LH levels were observed, resulting in significantly lower steroid production if calculated per large follicle. We conclude that the i.v. route is superior to the s.c. route in inducing multiple follicular growth in women with normal cycles.