Context The role of metabolic hormones, medicinal plants and their interrelationships in the control of human reproductive processes are poorly understood. Aims To examine how leptin, obestatin and ginkgo (Ginkgo biloba L.) affect human ovarian hormone release. Methods We analysed the influence of leptin and obestatin alone and in combination with ginkgo extract on cultured human ovarian granulosa cells. The release of progesterone (P), insulin-like growth factor I (IGF-I), oxytocin (OT) and prostaglandin F (PGF) were analysed by enzyme immunoassay and enzyme-linked immunosorbent assay. Key results Leptin addition promoted the release of all the measured hormones. Obestatin stimulated the release of P, IGF-I and OT and inhibited PGF output. Ginkgo suppressed P, IGF-I and OT and promoted PGF release. Furthermore, ginkgo changed the stimulatory action of leptin on PGF to an inhibitory one. Conclusions Leptin and obestatin are involved in the control of human ovarian hormone release and ginkgo influences their function. Implications Leptin and obestatin could be useful as stimulators of human ovarian cell functions. The suppressive influence of ginkgo on ovarian function should lead to the development of ginkgo-containing drugs.