In this era of molecular biology and the apparently novel subdiscipline of translational medicine, it is perhaps salutary to review briefly the background to the discovery of the thiazide diuretics, which, even 50 years after the initial research leading to their discovery, play a pivotal role in cardiovascular therapy.1,2 As so often in novel drug discovery, several seemingly unconnected scientific observations coincided to bring about the discovery of the thiazides. The first-generation diuretics were salts of mercury used primarily as topical antiseptics, especially in the management of syphilis, usually in the form of mercurous chloride (calomel)...