Endothelin has extensive effects on coronary VSMCs. Its actions include vasomotor control and growth promotion, thus implicating endothelin in the pathogenesis of various diseases including atherosclerosis, diabetes mellitus, and hypertension. The role of the peptide, with all of its ramifications, is still under investigation, but the advancing knowledge about the mode of action makes it possible to begin further work on the therapeutic applications of agonists and antagonists. ETA and ETB receptor antagonists already exist and have been found to have specific effects in animal models. Further studies should be undertaken to comprehend the physiologic and pathophysiologic roles of endothelin to take advantage of its numerous therapeutic implications.