Objective: To evaluate the pharmacokinetics of palonosetron hydrochloride in healthy volunteers. Methods: Thir-ty-one healthy volunteers were grouped into three palonosetron hydrochloride dosage regimens of 0.125, 0.25, and 0.5 mg. The plasma concentrations of palonosetron were determined by ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). DAS 2.1 software was applied to assess the plasma concentration-time data. Results:After intravenous injection of 0.125, 0.25, and 0.5 mg palonosetron to the subjects, the AUC0-168h values of palonosetron were (7.5±2.5), (15.2±4.0), and (34.8±9.7) μg· h·mL-1. The t1/2 values were (27.2±9.5), ( 27.2±6.5), and (31.4±5.6) h. Palonosetron exposure increased proportionally with the dose range of 0.125 mg to 0.5 mg. The correlation coefficient was 0.998. No grade 3 or grade 4 toxicity was observed during the study. Con-clusion:A rapid, sensitive, and selective UPLC-MS/MS method for palonosetron quantification in human plasma was developed and validated. All the participants indicated high tolerance throughout the study. Our data showed that palonosetron exhibits linear pharma-cokinetics over the the dose range of 0.125 mg to 0.5 mg.