Antiemetic effect and safety of concurrent administration of ondansetron and other antiemetics (dexamethasone, domperidone and ethyl loflazepate), given for complete suppression of nausea/vomiting, were examined in 46 patients (109 courses) with gynecological cancer receiving single high-dose of cisplatin or carboplatin. As for the delayed emesis, antiemetic effect depending on the steroid treatment duration, given concurrently to ondansetron, was compared. The results were as follows; 1. In 78 courses, anticancer drugs were given concurrently to cisplatin or carboplatin only on Day 1. In the remaining 31 courses, those drugs were concurrently administered up to Day 6 at the longest. 2. Complete suppression (i.e., no onsets) rate of acute emesis was 64.2% (70/109 courses) for nausea, and 84.4% (92/109 courses) for vomiting. 3. When the complete suppression depending on duration of concomitant steroid was examined mainly in patients receiving CAP (cyclophosphamide, adriamycin and cisplatin), higher antiemetic effect, especially in nausea, was observed in those on concomitant steroids for 3 days compared to that for 1 day. 4. The food intake rate improved along with nausea symptoms. 5. No adverse event or laboratory abnormality due to the multi-antiemetic treatment was observed. Based on the above, the efficacy of the antiemetic treatment in this study was confirmed. In delayed emesis, concurrent steroids given for 3 days after chemotherapy were considered effective and were also regarded to improve food intake.