Cancer patients consistently rank nausea and vomiting as the most feared side effects of treatment. Cisplatin, one of the most active chemotherapeutic agents, causes acute emesis and a delayed emesis syndrome, which also results in considerable patient morbidity. Despite the use of metoclopramide-containing combination regimens, approximately one third of cisplatin-treated patients continue to experience emesis. In recent years, considerable progress has been made in managing chemotherapy-induced emesis. This review discusses several factors that have contributed to improved antiemetic control, including standardization of antiemetic trial methodology, insight into the pathogenesis of chemotherapy-induced emesis, and the development of a new class of antiemetic agents, the serotonin antagonists. In clinical studies performed to date, these agents have generally proven to be both effective and safe. Three multicenter trials of the selective serotonin antagonist ondansetron in the prevention of nausea and vomiting from cisplatin are reviewed.