Olive oil is the main source of unsaturated fatty acids in the Mediterranean region, anutritional regimen gaining ever-increasing renown for its beneficial effects on inflammation, cardiovascular disease, and cancer. The present work aimed to study the protective effect ofOlive Oil against the histopathological alterations induced by (cholesterol 4%+ Cholic acid 1% + thiouracil 05%) in the aorta and Liver of rat.                                                             Olive oil and / or a mixture of (cholesterol 4%+ Cholic acid 1% + thiouracil 05%) were given to male rats for 16 wk, 12 h after the last diet animals were killed and the selected tissues obtained and prepared for histological study.       The obtained results demonstrated that treating rat with (cholesterol 4% + Cholic acid 1% + thiouracil 05%) induced sever histopathological changes in the liver ,these changes includeddisruption of liver architecture as it lost the normal radiating pattern, cellular infiltration and cells turned into large "foam cells" contained  cytoplasmic vesicles. Also, aorta with straight tunica intimae has large subendothelial deposits of lipid; many myofibrils were disorganized and destroyed containing dense irregular nuclei, tunica media increased till 58.8µm.             Co-administration of olive oil+mixture of (cholesterol 4% + Cholic acid              1% + thiouracil 05%) lessened most histopathological changes in a aorta and liver as compared to animals treated with the mixture of (cholesterol 4% + Cholic acid 1% + thiouracil 05%) alone. This indicatedthat olive oil showed improvement in the structure of the aorta and liver of rat. So the usage of olive oil was recommended for healthy life.