Dietary products like cocoa with high flavonoids may play a role to boost the integrity of the liver against insults resulting from myocardial injury. Twenty-four male Wistar rats, divided into four groups of 6 rats were used for the study. Group 1 was control and received 0.9% normal saline via oral gavage. Group 2 was the acute myocardial injury group, and received two doses of subcutaneous injection of isoproterenol (100 mg/kg body weight) at an interval of 24 hours between doses. Group 3 was administered Theobroma cacao (100 mg/kg body weight orally) only for 2 weeks. Group 4 was pretreated with Theobroma cacao for 2 weeks and then followed by injection of isoproterenol (100 mg/kg body weight) on day 15 and 16. At the end of the experimental period, the rats were euthanized and serum collected for laboratory investigations of lactate dehydrogenase, troponin, alanine aminotransferase, aspartate transaminase, and alkaline phosphatase. Administration of isoproterenol resulted in a significant (p<0.001) elevation in the serum concentrations of the cardiac biomarkers, troponins and LDH when compared with the control group. Pretreatment with Theobroma cacao before myocardial infarction caused a significant (p<0.01) reduction in the concentrations of LDH and troponins with values similar to the control group. The serum liver enzymes AST, ALT, and ALP levels were also significantly (p<0.01) but were reversed in the Theobroma cacao cocoa treatment groups. It is concluded that Theobroma cacao prevents hepatic and heart damage thus providing a support for the prophylactic use of dietary Theobroma cacao against hepatotoxicity.