OBJECTIVE To assess the efficacy and tolerability of a combination of ramosetron and dexamethasone compared with ramosetron alone in the prevention of cisplatin-induced emesis. METHODS Prospective, randomised, single-blind, crossover study. METHODS Thirty-four chemotherapy-naive patients with stomach cancer or sar-coma scheduled to receive two consecutive courses of cisplatin-based chemo-therapy. METHODS Patients were randomised to receive ramosetron (0.3mg intravenously [IV] on day 1 then 0.1mg orally [PO] once daily on days 2-6) either with or without dexamethasone (20mg IV on days 1-6). Those who completed the first chemotherapy cycle returned for a second cycle after 4 weeks and were crossed over to the alternate antiemetic treatment. RESULTS In the first 24 hours, complete response was achieved in 84.8% of patients receiving ramosetron plus dexamethasone and in 59.4% of patients receiving ramosetron alone (p = 0.014). Furthermore, the combination ramosetron plus dexamethasone was significantly more effective in terms of time to first episode of vomiting and patient's preference. On day 2, patients who received ramosetron plus dexamethasone had a higher complete response rate than those who received ramosetron alone (p = 0.047). Adverse events were mild with no significant differences between the two groups. CONCLUSIONS The combination of ramosetron plus dexamethasone was superior to ramosetron alone in preventing cisplatin-induced acute emesis. It is highly recommended that a combination of ramosetron plus dexamethasone rather than ramosetrone alone be given to patients receiving cisplatin-containing chemo-therapy.