Major progress in the ability to control chemotherapy-induced emesis has been made over the past 10 years. One of the several factors contributing to this improved control has been the development of accurate assessment methodology. The application of proper study methodology fostered the identification of active single agents and led to the formation of effective anti-emetic combinations. In this communication, important areas in anti-emetic study evaluation will be outlined. Proper methodology includes selection of agents or regimens that have a good rationale for study. Patient, chemotherapy, and anti-emetic factors must be controlled or standardised in good trial design, and the evaluation techniques for determining the amount of emesis or of nausea must be performed using reliable and valid methods. The statistical design employed and number of patients entered in the trial should be determined based on achievable and relevant goals.