Many of the drugs currently used in medical practice are racernates.The enantiomers of a racemic drug differ in pharrnacodynamics and/or pharmacokinetics,thus in some cases it is preferable to develop pure enantiomers by racernic switch.In a recent study by Pai eta/, dexrabeprazole [R(+)-rabeprazole] (10 mg) was found to be more effective than rabeprazole (20 rag)in the treatment of gastroesophageal reflux disease.We read with great interest in this study and discussed whether such racernic switch would be applicable to other proton-pump inhibitors (PPIs).A literature review indicates that stereoselective pharmacokinetics, rather than stereoselective pharmacological activity, is the main cause of differences in clinical efficacy between pure enantiomer and racernic PPI.Racemic switches of PPI provide the therapeutic advantages such as reducing metabolic load on the body, simplifying pharmacokinetics,providing benefit to the non-responders to standard dose of racemate, more homogenous response to treatment and better efficacy with equal safety.Further studies in quantitative structure-activity relationships (QSARs) are needed to address the fact that the preferred enantiomer of PPI is not always in the same absolute configuration,i.e., S-form is for omeprazole, pantoprazole and tenatoprazole whereas R-form is for lansoprazole and rabeprazole.