The efficacy of ondansetron in acute and domperidon in delayed nausea, vomiting and loss of appetite and their continued efficacy during the three subsequent courses were determined. Thirty-one breast cancer patients on a chemotherapy regimen consisting of 5-fluorouracil, epirubicin and cyclophosphamide were treated with oral ondansetron, 8 mg three times daily during the first day and oral domperidon, 20 mg three times daily during the subsequent two days. This combination was used as long as it continued to be of antiemetic value. During the first course global control of acute nausea, vomiting and conservation of appetite were achieved in 55%, 77% and 55% of the patients, respectively. Global control of delayed nausea and vomiting and conservation of appetite were achieved in 58%, 74% and 58% of the patients according to the worst day analysis, respectively. The cumulative antiemetic effect of ondansetron decreased from 77% (Cl 62-92%) to 47% (Cl 29-66%) and domperidon from 74% (Cl 59-90%) to 53% (CI 35-71%) during the three subsequent courses. This combination seems to be effective but comparative studies are needed.