Objective To study the effect of omeprazole on serum concentration and pharmacokinetics of oxiracetam in Chinese healthy male volunteers and established high performance liquid chromatography (HPLC) method for determination of oxiracetam in plasma.Methods This was a single center,opened,two-way crossover study.Eight healthy Chinese volunteers were screened.The concent ration of oxiracetam in plasma was detected by HPLC before and after omeprazole administ ration.Pharmacokinetics parameters were evaluated by DAS 2.1.1 pharmacokinetics programme.Statistical analysis was performed with SPSS11.5 software.Results The results showed that after oxiracetam was used alone and incombination with omeprazole,pharmacokinetic parameters of AUC0-t,AUC0-∞,MRT0-t,MRT0-∞,tmax,Cmax,t1/2,CL/Fand V/F had no significant difference.Conclusion HPLC method for determinating of oxiracetam concentration in plasma is rapid,simple,accurate and sensitive.There is no influence on the pharmaco-kinetics of oxiracetam when combined with omeprazole in humans.