This randomized, double-blind crossover study was undertaken to compare the antiemetic effectiveness of intravenous prochlorperazine (Compazine) and lorazepam (Ativan) in the management of postchemotherapy symptoms during two initial cycles of therapy. Each patient received at least one treatment as an outpatient. Data from the 24 patients receiving noncisplatin therapy who completed the crossover study were evaluated for antiemetic efficacy and total posttherapy symptom experience. Although results indicated no statistically significant difference between regimens in the control of posttherapy nausea and vomiting, these side effects were completely controlled in 26 of the 48 study treatment cycles. Lorazepam significantly reduced total posttherapy symptom experience by decreasing patients' experience of fatigue and pain. Findings support the value of lorazepam in antiemetic regimens and point to the need for further examination of antiemetic combinations.