Coronary artery spasm (CAS) plays an important role in the pathogenesis of ischemic heart disease. The clinical manifestations of CAS include variant angina, myocardial infarction and sudden death. Although endothelial dysfunction and hyperreactivity of vascular smooth muscle cells have been associated with CAS, the underlying mechanisms remain unclear. Thus, there is a long way to go to truly understand the pathogenesis of CAS to formulate effective treatments. This article discusses the pathophysiological mechanisms as well as downstream molecular pathways of CAS, with a focus on potential therapeutic targets.