The development of enantioselective chromatographic techniques has mad
e it feasible to routinely follow the metabolism and disposition of th
e separate enantiomers of a chiral drug. These studies are a source of
data about in vivo pharmacological processes. The key question is rec
ognition of the fundamental information contained within the results a
nd the application of this data to the development of a deeper underst
anding of the clinical consequences of stereochemistry. This manuscrip
t presents two examples of how chirality can be used as a unique probe
of basic pharmacological properties.