A chiral sulfoxide is an important group in many bioactive molecules, and its absolute configuration often has substantial effects on its biological activity. Compounds that contain tri-coordinated sulfur atoms in a pyramidal structure can exist in different optically active forms. Omeprazole is a highly successful sulfoxide drug and the first registered substance in the proton pump inhibitor class, whose chirality may significantly impact its interaction with biological targets. The R-enantiomer of omeprazole is rapidly metabolized. In contrast, the clearance of the S-enantiomer occurs at a much slower rate. Viewing this, further attention should be paid to the pharmacological and toxicological studies of individual enantiomers of chiral drugs, and thus led to an exigent demand for enantioseparation.