This study was designed to evaluate the cardio protective effect of the semi-purified flavonoids from banana blossoms on the basis of histopathological parameters and biochemical analysis in isoproterenol induced myocardial infarction in rats. The semi-purified flavonoids extract were used to pretreat Sprague Dawley rats for 19 days at doses 50mg/kg, 100mg/kg and 150 mg/kg. Aspirin was used as the positive control, and was given orally at a dose of 12 mg/kg. After pretreatment, two doses of isoproterenol (85mg/kg body weight per dose, subcutaneously) were injected to rats at an interval of 24 hr for two days (20th and 21st day) to induce myocardial infarction. Twenty-four hours after the last dose of isoproterenol, all rats were sacrificed via cervical dislocation. In comparison with the negative and positive control, results showed that at doses 100mg/kg and 150mg/kg, the semi-purified flavonoids extract did not exhibit cardio protection. At 50mg/kg, the semi-purified flavonoids extract exhibited cardio protection comparable to that of Aspirin hence indicating that the semi-purified flavonoids from banana blossom has a cardioprotectiveeffect against isoproterenol-induced myocardial infarction in rats.