“Bust enhancing” herbal products are widely advertised. No clinical trials have been published. These products contain a variety of ingredients, including grains, hops, saw palmetto, dong quai, chaste-tree berry, wild yam, kava, fennel, black cohosh, and fenugreek. Several of these herbs are hormonally active; for example, hops contain 8-prenylnaringenin, a phytoestrogen that is more potent than other dietary phytoestrogens. Many bust-enhancing dietary supplements contain substrates for Fusarium, a fungus that produces zearalenone, a potent estrogen that has been associated with breast enlargement in humans and other species. The use of bust-enhancing products should be discouraged because of lack of evidence for efficacy and long-term safety concerns.