BACKGROUND Carthamus tinctorius injection (CTI) is a traditional Chinese medicine (TCM) specifically used for the treatment of cerebral ischemia and myocardial ischemia. OBJECTIVE This study evaluated the protective effects of CTI on isoprenaline-induced acute myocardial ischemia (AMI) in rats and explored the underlying mechanisms. METHODS (i) Sprague-Dawley rats were randomly divided into 5 groups: control, myocardial ischemia model, and high-, low-dose of CTI groups (2.5 and 0.625 g/kg, respectively, i.p. for 5 days), and Xiang-Dan (20 g/kg) group (n = 10 in each group). AMI was induced by isoproterenol (5 mg/kg) by intraperitoneal injection. Assessment of electrocardiograms (ECG) was carried out. (ii) Another 40 rats were randomly divided into 5 groups, the concentration of IL-6 and TNF-α in serum were measured by radioimmunological assay; Bcl-2 and Bax protein expression were measured by immunohistochemistry. RESULTS CTI (2.5 and 0.625 g/kg) significantly inhibited the typical ECG S-T segment elevation, reduced concentration of IL-6 and TNF-α in serum, suppressed overexpression of Bax protein and also inhibited the reduction of Bcl-2 expression and markedly depressed the Bax/Bcl-2 ratio. CONCLUSIONS These findings demonstrate that CTI is cardioprotective against AMI in rats and is likely to related to decrease inflammatory response mediated by TNF-α and IL-6, down-regulate protein level of Bax and up-regulate that of Bcl-2 in the heart tissue.