Purpose To evaluate the effect of a high-fat diet on the pharmacokinetics(PK)and safety of flumatinib mesylate tablets.Methods In this open-label crossover trial,the subjects received a single 400-mg dose of flumatinib after a high-fat diet or fasting.After a 14-day washout period(including a 5-day PK assessment),a second 400-mg dose of flumatinib was offered under the opposite condition,followed by a 5-day PK assessment.Blood samples for PK analyses were collected at baseline(at Days 1 & 15)and up to 96 h post-dosing.The plasma concentrations of flumatinib and its metabolites of M3 and M1 were validated by liquid chromatography-tandem mass spectrometry(LC-MS/MS).The area-under-curve(AUC)and Cmax of natural logarithmic transformation were analyzed by a mixed model.Results The high-fat diet/fasting ratios of geometric least-squares means for AUC0-t and AUC0-∞ were 167.43%(143.92%-194.79%)and 166.87%(143.47%-194.09%)and for maximal plasma concentration(Cmax)281.65%(225.80%-351.31%)respectively.Furthermore,other laboratory tests,vital signs,electrocardiogram and physical examination showed no clinical significance.Conclusion A single oral dose of flumatinib is both safe and well-tolerated in Chinese volunteers.However,a high-fat diet has impact upon the PK of flumatinib so that dosing is ideal under a fasting condition.