['Sulfur dioxide was considered to be toxic and detrimental to human health. However, this review highlights recent advances that suggest sulfur dioxide might be a novel endogenous gaseous signaling molecule involved in the regulation of cardiovascular functions.', 'The data used in this review were mainly from the studies reported in Medline and PubMed published from 1986 to 2010.', 'Original articles and critical reviews selected were relevant to exogenous and endogenous sulfur dioxide.', 'The sulfur dioxide/aspartate amino transferase pathway is endogenously generated in the cardiovascular system, and sulfur dioxide shows broad bioactive effects, such as antihypertension, vasodilation, and amelioration of vascular remodeling. A disturbed sulfur dioxide/aspartate amino transferase pathway is known to be involved in the pathogenesis of many cardiovascular diseases, such as ischemia-reperfusion injury, monocrotaline-induced pulmonary hypertension, athrosclerosis, spontaneous hypertension and hypoxic pulmonary hypertension. Furthermore, in experimental studies the prognosis of these cardiovascular diseases can be improved by targeting endogenous sulfur dioxide.'] Does sulfur dioxide act as a novel endogenous gaseous signaling molecule in the cardiovascular system?