Clomiphene citrate (CC) and follicle stimulating hormone (FSH) are the two main modalities used for ovarian stimulation (OS). Decisions are based not only on randomized clinical trials (RCT), but also on other basic science and clinical evidence supporting their use. This chapter presents the effectiveness of adjuncts in enhancing outcomes in women having OS for in-vitro fertilization (IVF). The adjuncts include leuprolide acetate (LA) and gonadotropin-releasing hormone (GnRH) agonists, oral contraceptive (OC) pretreatment, estrogen pretreatment, dexamethasone (DEX), metformin (Met), human chorionic gonadotropin, aspirin (ASA), growth hormone (GH), dopamine agonists, and androgens and androgenic drugs. Most of these adjuncts are medications approved for other uses but not specifically as adjuncts for OS. The risk/benefit ratio in their use is quite favourable. Adjuncts aimed at improving ovarian response by increasing ovarian androgen concentrations appear to have real promise, but require further well-controlled studies to verify their effectiveness.