The preventive effects of quercetin against aortic aneurysm or dissection were examined using two different mouse models, which were designated as AB, by taking the acronym of two administered drugs; angiotensin II (Ang II) + β-aminopropionitrile (BAPN)-treated aortic aneurysm model mice, and LAB, by taking the acronym of three administered drugs; Nω-nitro-l-arginine methyl ester (l-NAME) + Ang II + BAPN-treated aortic dissection model mice. This evidence concerns the gene AGT and Aortic dissection.