Background/aim: An aneurysm is a pathological enlargement of an artery characterized by the thinning of the elastic fiber layer in the tunica media. Because the aneuritic artery wall is weakened, these vessels can rupture and cause serious bleeding. Surgical methods are often used for the treatment of aneurysms. However, cell-based therapies are less invasive and potentially safer alternatives. In this study, the therapeutic efficacy of rat adipose tissue-derived mesenchymal stem cells (MSCs) was investigated in a new carotid artery aneurysm model.