Carthamin yellow (CY) is a flavonoid compound isolated from safflower, which is widely used clinically in China. It has various pharmacological effects including promoting blood circulation to remove blood stasis and alleviating pain. Ischemic heart disease is one of the main culprits of illness and death. Here, in this study, ex vivo and in vivo models were used to investigate whether CY reduces ischemia/reperfusion injury. In vitro experiments further verify and explain the potential mechanisms of CY cardioprotective function. Isolated hearts from male rats with or without CY pretreatment before ischemia which underwent 30-minute ischemia followed by 60-minute reperfusion showed that CY pretreatment significantly reduced the infarct size and lactate dehydrogenase release. The in vivo experiments also indicated CY preadministration (i.v.) reduced infarct size and improved the heart function, which was impaired by myocardial ischemia/reperfusion injury. The in vitro model on myocardial cell also showed that CY reduced ischemia/reperfusion injury by reducing the lactate dehydrogenase and reactive oxygen species (ROS) releasing. Eliminating ROS with N-acetylcysteine or preinject CY into rat jugular vein reduces the expression of IL-6, TNF-a, and, especially, IL-1b in an in vivo I/R model. Also, CY pretreatment strongly reduces ischemia/reperfusion-induced NLRP3 up-expression and caspase-1 activation. Our results indicated CY reduced ischemia-reperfusion injury when administered before reperfusion. The reduction in injury is accompanied by a reduced ROS release and decreased inflammatory response.