Studies on the effects of garlic (Allium sativum) on hyperlipidemia have demonstrated somewhat controversial results and there have been few studies on its enzymatic mechanism. The purpose of this study was to assess the effect of garlic on the liver phosphatidate phosphohydrolase (PAP) activity, plasma lipid levels, malondialdehyde (MDA) and plasma antioxidant in rats fed either by normal or high-lipogenic diet with or without garlic. Male Wistar rats were fed by standard pellet diet (group I), standard diet supplemented with 4% garlic (group II), lipogenic diet (containing sunflower oil, cholesterol and ethanol) plus 4% garlic (group III) and only lipogenic diet (group IV). Results showed that garlic significantly reduced total cholesterol (TC), plasma triglyceride (TG), LDL-C, VLDL-C, liver triglyceride, plasma malondialdehyde (MDA) and elevated plasma antioxidant in garlic treated rats (groups II and III) compared to group IV (lipogenic diet group). Also, liver PAP activity was decreased in group II than group I whereas, the decrease in its activity in groups III and IV was due to the accumulation of triglyceride in liver. Therefore, the results are clearly indicative of the beneficial effects of garlic in reducing lateral side effects of hyperlipidemia.