It is widely perceived at present that pharmacogenetics and pharmacogenomics are about to revolutionize the face of medicine. In a more realistic assessment, the implementation of molecular genetics and biology will provide us with better ways to treat illnesses, and has already begun to do so in an incremental and evolutionary fashion. However, it is unlikely to change fundamentally the direction of medical progress. Advances are most likely to be made in the area of pharmacodynamics, as we learn to differentiate broader conventional clinical diagnoses into separate molecular subtypes.