Nausea and vomiting are two of the most feared side effects of cancer chemotherapy and radiotherapy. Chemotherapy-induced nausea and vomiting can be broadly categorized as acute (occurring within 24 hours of therapy), delayed (persisting for 6-7 days after therapy), or anticipatory (occurring prior to chemotherapy administration). Breakthrough and refractory nausea and vomiting describe the symptoms of uncontrolled emesis. Evidence suggests that good control of nausea and vomiting during the acute period correlates with the control of delayed emesis. Conversely, protection failure during the first 24 hours has a high predictive value for delayed emesis in the same cycle. The 5-HT(3)-receptor antagonists, regarded as the 'gold standard' in antiemetic therapy, are the first-line treatment for moderately and highly emetogenic chemotherapy and radiotherapy regimens in adults and children. Evidence suggests that the 5-HT(3)-receptor antagonists administered in combination with corticosteroids afford the best protection from symptoms of acute emesis and, by extrapolation, the most effective prevention of delayed emesis. Antiemetic therapeutic guidelines stress that the goal of therapy is to prevent cytostatic-induced nausea and vomiting. Therefore, the prophylactic use of the most effective antiemetic regimen-taking into consideration the emetogenicity of the chemotherapy and individual patient characteristics-must be adhered to in order to prevent acute, delayed, and anticipatory nausea and vomiting.