In patients with poor response to ovarian stimulation with gonadotrophins, growth hormone (GH) is sometimes used to increase paracrine insulin-like growth factor-1 (IGF-1) effect. We postulated that dehydroepiandrosterone (DHEA) administration to poor responders would augment gonado-trophin effect via a similar mechanism. Baseline ovarian stimulation response to a cycle with DHEA in five healthy non-smoking women <41 years old was compared with day 3 FSH <20 mIU/ml. All had documented poor response to vigorous gonadotrophin administration. After day 2 ultrasounds, DHEA-sulphate (DHEA-S), FSH, human chorionic gonadotrophin (HCG), and testosterone were measured, and the women were given 80 mg/day of oral micronized DHEA for 2 months. While still on DHEA, they underwent ovarian stimulation with FSH given i.m. twice a day, and HCG (10 000 IU) at follicular maturity, followed by intrauterine insemination. Cycle parameters assessed were peak oestradiol, and peak oestradiol/ampoule. The DHEA/ovarian stimulation cycles occurred between 4 and 24 months after the control cycles. After 2 months DHEA treatment, DHEA-S increased to 544 +/- 55 microg/dl, and testosterone increased to 67.3 +/- 6.1 ng/dl. All five subjects (six cycles; one subject had two DHEA cycles) had increased responsiveness; peak oestradiol concentrations increased from 266.3 +/- 69.4 pg/ml to 939.8 +/- 418.9 pg/ml. The oestradiol/ampoule ratio increased in all six cycles, by a mean of 2.94 +/- 0.50 fold (P = 0.012). One of the cycles resulted in a delivered twin pregnancy. In this small series, DHEA improved response to ovarian stimulation even after controlling for gonadotrophin dose. Supplemental DHEA treatment during ovarian stimulation may represent a novel way to maximize ovarian response.