Background: Since long high fat diet (HFD) is being blamed for causing fatty degeneration of liver and formation of atheromatous plaques. At present, no proper pharmacotherapy is available for both the conditions. In this study, different substances containing monounsaturated fatty acids were used to observe their protective effects in the HFD induced damage to liver and coronary vessels. Objectives: To discover effective therapeutic agents for HFD induced fatty degeneration of liver and atheromatous plaques. Materials and Methods: The study was conducted from September 2015 to April 2016. In this study, rats were divided into nine groups according to dietary regimen. Each group comprised six rats. Saturated fat was given in the form of butter, and unsaturated fat was given in the form of corn oil, olive oil, Nigella sativa oil, and crushed garlic. Serum samples were taken to estimate lipid profile, liver functions, cardiac functions, and kidney functions. Visceras were removed after animal sacrifice, and histopathological examination was done. Results and Conclusion: During the study period, the weight of animals changed significantly in some groups. Those animals which were given crushed garlic along with high saturated fat diet, showed protection against accumulation of lipids in the hepatocytes. Olive oil and Nigella sativa oil were comparatively less effective.