酒精不耐症(alcohol intolerance)被認為與遺傳有關，由於先天基因問題，導致身體缺乏酒精代謝過程中所需要的乙醛去氫酶(aldehyde dehydrogenase 2, ALDH2)。在這種情況下，身體無法有效地分解酒精代謝過程產生的乙醛，導致這種有毒物質堆積在身體內，攝入後幾分鐘內即能產生急性期症狀，如頭暈、頭痛、噁心嘔吐、心搏過速、肢體無力、皮膚發紅等。反覆暴露在此狀態下，則可能致使肝臟損傷、心血管問題和癌症（口腔癌、口咽癌、食道癌、大腸癌等）風險增加。酒精不耐症是由於一個特別的基因錯義(missense)變異，即E504K（單核苷酸多態性(single nucleotide polymorphism, SNP) ID rs671，G>A）或稱作ALDH2*2等位基因，這個變異在東亞地區特別盛行，影響了大約5.4億東亞人，即全球人口的8%。在我們身處的東亞與全世界其他地區相比，有著較高的盛行率，約在20%至30%左右。其中，臺灣甚至有著高達49%的民眾有ALDH2的基因變異，是全球比率最高的地方。華人的飲酒文化可追溯至上千年前，隨著近年來基因技術的迅速發展，學者期望這些技術能深入揭示酒精不耐症相關基因可能導致的疾病機制，並透過藥物治療或基因編輯技術來降低相關健康風險。 此文章整理了酒精在人體中的代謝途徑、酒精不耐症的流行病學分布情況、酒精不耐症可能致使的疾病風險以及基因研究上的現況以及展望。

Alcohol intolerance is generally considered genetically linked to a congenital deficiency of aldehyde dehydrogenase 2 (ALDH2), an enzyme essential for alcohol metabolism. This deficiency impairs the breakdown of acetaldehyde, a toxic byproduct of alcohol metabolism, leading to its accumulation in the body. Acute symptoms of alcohol intolerance, typically appearing within minutes of alcohol consumption, include dizziness, headache, nausea, vomiting, tachycardia, muscle weakness, and facial flushing. Chronic exposure to elevated acetaldehyde levels increases the risk of liver damage, cardiovascular diseases, and cancers, including those of the oral cavity, oropharynx, esophagus, and colon. Alcohol intolerance is caused by a specific missense mutation in the ALDH2 gene, known as E504K (single nucleotide polymorphism rs671, G>A), or the ALDH2*2 allele. This mutation is particularly prevalent in East Asia, affecting approximately 540 million individuals, or about 8% of the global population. The prevalence in East Asia is significantly higher, ranging from 20% to 30%, with Taiwan reporting the highest rate, where nearly 49% of the population is affected. This review examines the mechanisms of alcohol metabolism, the epidemiology and health risks of alcohol intolerance, and future directions in genetic research on this condition.