Obesity causes structural and functional damage to various organs. Quercetin is a flavonoid and has potent antioxidant, antiapoptotic and anti-inflammatory effects in the body cells. This study aims to investigate the therapeutic effect of Quercetin on the cardiac effect caused by obesity in rats with experimental obesity using biochemical and histological methods. In this study, 24 male Sprague Dawley rats were used. The rats were divided into three groups i.e., control, obese, and Quercetin-Obese. A high-fat diet was administrated to the obese groups for 3 months, the other groups were fed with normal pellet forage. After the formation of obesity, a 50 mg/kg dose of Quercetin was orally fed to the quercetin-obese and quercetin groups for 15 days. At the end of study, all the animals were sacrificed by taking blood under anesthesia (sevoflurane), and their heart tissues were taken. In the obtained serum samples, the levels of triglyceride (TG), cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and cardiac troponin-I (cTnI) were measured by the auto-analyzer device. The heart tissues were stained with Bax and Bcl-2 antibodies as immuno-histochemical. When the results of the analysis were compared among the control and other groups, it was shown that obesity increased the levels of serum TG, CHOL, LDLC, and cTnI whereas quercetin administration had a decreasing effect on these parameters (P