The antiemetic effect of graded, single high-dose intravenous dexamethasone was studied in 27 patients receiving combination chemotherapy with either doxorubicin (50 mg/m2) or cis-platinum (100 mg/m2). A total of 57 cycles were individually evaluated, utilizing a detailed rating system. Nausea and vomiting did not occur in 20 of 57 cycles; in 17, the chemotherapy was doxorubicin-based, and in 3 it was cis-platinum-based. Of the 37 cycles associated with nausea and vomiting, 32 contained Cis-platinum and 5 doxorubicin. The average dexamethasone dosages for doxorubicin and platinum-containing combinations were 40 and 95 mg/m2, respectively. Side effects included a dose-dependent sensation of perineal pruritis (11 patients, 17 cycles) lasting for serveral minutes, and subjective feelings of increased appetite and well-being. Dexamethasone administered intravenously 15 min prior to chemotherapy in a dose of 40 mg/m2 apparently provides highly effective antiemetic protection for patients receiving treatment cycles containing doxorubicin; however, for patients receiving regimens containing cis-platinum, the antiemetic effect of dexamethasone as a single agent is limited.