We studied the prevalence of anticipatory nausea (AN) and anticipatory nausea and vomiting (ANV) in an ambulatory medical oncology population by self-report questionnaire over 7 weeks. Thirty-eight of 123 (31%) patients receiving parenteral chemotherapy reported anticipatory symptoms (AN or ANV). Twenty-one (17%) patients reported ANV and 17 (14%) reported AN only. Patients receiving parenteral chemotherapy (N = 123) with anticipatory symptoms (N = 38) were younger (45.1 +/- SE 1.9 vs 55.5 +/- 1.45, P less than 0.001) and more likely to be female (82% vs 61%, P = 0.04), unmarried (47% vs 26%, P = 0.03), and receiving adjuvant chemotherapy for breast cancer (42% vs 7% P less than 0.001) than patients without anticipatory symptoms (N = 85). A greater proportion of patients with both postchemotherapy nausea and vomiting and anticipatory symptoms reported greater than 12 hours of postchemotherapy nausea (65% vs 39%, P = 0.01) and postchemotherapy nausea and vomiting (37% vs 12%, P = 0.01) after their most recent cycle of chemotherapy than did patients with postchemotherapy symptoms only. In structured interviews with 23 patients with anticipatory symptoms, 16 identified specific stimuli associated with AN or ANV, taste being the most frequently mentioned (ten of 16 patients) sensory modality. In our clinic, patients receiving adjuvant chemotherapy for breast cancer develop anticipatory symptoms frequently and represent a relatively homogenous sample for further studies.