Aldehyde dehydrogenase 2 (ALDH2) is an important enzyme protecting human from the accumulation of aldehyde, the main metabolites of alcohol. The deficiency of ALDH2 gene results in flush and hang over post drinking and most importantly it has been found associated with the incidence of cancer and post myocardial infarction (MI) heart failure. In the previous studies, ALDH2 decreased the ischemic territory post infarction and using a large scaled interaction of genetic variants and ALDH2 as an instrument, the threats of alcohol consumption on Asians' cardiovascular health was underscored. Furthermore, in a meta-analysis reviewing 12 case-control studies also indicated an increase of 48% risks in patients with ALDH2 deficiency. Notably, the genetic deficiency is most prevalent in Asians. In Taiwan one of every two individuals may be the victim and the high prevalence is counted as the top of the world. However, a large scaled prospective study focusing on the prevalence of ALDH2 deficiency in patients with peripheral artery occlusive disease (PAOD) or acute coronary syndrome （ACS）remains lacking.