Oncology nurses and patients identify nausea and vomiting as the two most distressing side effects of chemotherapy. The onset and duration of nausea and vomiting in patients receiving chemotherapy may vary. Inadequate control of emesis in the first 24 h following chemotherapy can lead to anticipatory nausea and vomiting and poor control in subsequent cycles of treatment. It may also result in delays or refusal by the patient to have further treatment. In addition, excessive nausea, as well as vomiting, can lead to a multitude of physical, psychologic, and social problems. It is therefore important that nausea is controlled equally as well as vomiting. Recent clinical research into new antiemetic therapy has highlighted the need for standard criteria for the assessment of nausea and vomiting. Assessment should include nausea as a separate phenomenon that may occur in the absence of vomiting and can be equally, if not more, distressing. Objective measures are suitable for the assessment of vomiting, but are not available for assessment of nausea because it is a subjective phenomenon. The purpose of this article is to present evidence supporting the idea that patient reporting using a four-point scale may be a reliable indicator of the degree of nausea and antiemetic efficacy.