Abstract: Objective To investigate the efficacy and safety of palonosetron hydrochloride combined with decreased dexamethasone in prevention of nausea and vomit induced by cisplatin.Methods All cases were randomly divided into two groups,29 cases in control group (treated with palonosetron 0.25mg) and 31 cases in combined group (treated with palonosetron 0.25 mg and dexamethasone 5 mg).Results Effective rate of acute vomit in combined group was higher than that in control group [77.4% (24 cases) vs 75.9% (22 cases),P>0.05] ; effective rate of delayed emesis in combined group was also higher that in control group,the difference was statistically significant [83.9% (26 cases) vs 69.0% (20 cases),P <0.05].Increased incidence of blood pressure and serum glucose,insomnia,agitation,skin rash were observed when dexamethasone was used.Conclusion Palonosetron hydrochloride combined with decreased dexamethasone is effective and safe for prevention of delayed nausea and vomit induced by cisplatin.