The University of Illinois at Chicago/National Institutes of Health Center for Botanical Dietary Supplements Research began in 1999 with an emphasis on botanical dietary supplements for women's health. We have concentrated on plants that may improve women's health, especially to reduce hot flashes in menopausal women, alleviate the symptoms of premenstrual syndrome, and reduce persistent urinary tract infections. The primary focus of this article is to describe the operation of our center, from acquiring and identifying botanicals to isolating and identifying active constituents, to elucidating their mechanisms of action, and to conducting phase I and phase II clinical studies. Black cohosh (Actaea racemosa; syn Cimicifuga racemosa) has been used as a model to illustrate the steps involved in taking this plant from the field to clinical trials. Bioassays are described that were necessary to elucidate the pertinent biological studies of plant extracts and their mechanisms of action. We conclude that this type of research can only be successful with the use of a multidisciplinary approach.