代謝異常相關脂肪肝病是新興且快速增長之重要肝病，並已取代病毒性肝炎成為全世界包括台灣最常見之慢性肝病。代謝異常相關脂肪肝病疾病病程中大部分為單純脂肪變性或合併輕微發炎，少部分為脂肪肝炎。然而一旦進展為脂肪肝炎就可能產生肝臟纖維化，進一步惡化為肝硬化甚至產生肝癌。代謝異常相關脂肪肝病主要是代謝及環境等危險因子，加上基因與表觀基因變異，腸道微菌等諸多因子的交互作用而產生並導致其疾病進展。但其確切致病機轉與每個危險因子具體貢獻如何目前仍不明確，有待進一步研究了解，進而發展相關治療方式以改善患者預後。

Metabolic dysfunction associated fatty liver (MAFLD) is the emergent and rapid growing liver disease. It has become the post common chronic liver disease worldwide including Taiwan. Simple steatosis or with mild inflammation is found in a large proportion of MAFLD patients, and steatohepatitis is found in only a small part of patients. Once steatohepatitis is developed, patients may progress to liver cirrhosis or hepatocellular carcinoma. The development and progression of MAFLD are the interactions of multiple risk factors including metabolic, environmental, genetic and epigenetic risk factors, and gut microbiota. However, the exact pathogenesis of MAFLD and contribution of each risk factor remain uncertain, and need further investigation to develop associated treatment for the outcome improvement.