AIM: To study the effect of xin-tong capsule on nitric oxide production and cGMP content of ventricular myocardium in rats with experimental myocardial ischemia. METHODS: Rat model of acute myocardial ischemia induced by pituitrin was used in this study, and the lift of ST segment in ECG was used as the index of myocardial ischemia. The NO - 2/NO - 3 and cGMP contents of ventricular myocardium in rats with myocardial ischemia were determined.RESULTS: NO - 2/NO - 3 and cGMP contents in ventricular myocardium of myocardial ischemia were (486?59) nmol/g protein and (0.38?0.08) nmol/g protein, respectively, and markedly lower than those of control [(1057?145) nmol/g protein and (0.70?0.09) nmol/g protein] ( P