近年來，台灣由於肥胖與代謝症候群比例增加，非酒精性脂肪肝疾病的患者也逐年上升。非酒精性脂肪肝疾病是肝臟脂肪的過度堆積所造成，進一步再依照肝臟細胞是否有發炎損傷來區分為脂肪肝炎，或者是單純的非酒精性脂肪肝。兩者自然病程與預後相距極大，脂肪肝炎由於肝臟慢性的發炎，長期可能轉變為肝硬化，同時有較高的死亡率，相對於非酒精性脂肪肝則無。因此，對於臨床上懷疑是非酒精性脂肪肝疾病的患者，首先要確定診斷--取得影像或是組織學上肝臟脂肪堆積的證據，同時排除酒精、藥物、先天性疾病等次發性的因素造成，之後再做進一步的整體肝臟功能評估，以及肝臟酵素指數檢查，來評估是否有脂肪肝炎或甚至纖維化的情況。治療上，首要就是個人化的生活習慣調整，接著治療相關的代謝疾病--肥胖、高血脂、胰島素抗性、第二型糖尿病等，最後則是針對有明顯肝臟發炎的病人做藥物治療的考量。本文就近期的資料，從診斷、評估、追蹤、到處置，做一個全面性的整理，以期能給所有非酒精性脂肪肝疾病患者一個完整的評估與照顧。

Non-Alcoholic Fatty Liver Disease (NAFLD), caused by excessive accumulation of fat in liver, is histologically categorized into either Non-Alcoholic Steatohepatitis (NASH) or Non-Alcoholic Fatty Liver (NAFL) depending on the presence of hepatocellular inflamed damage. With the liver suffering from chronic inflamed damage, patients with NASH may progress to cirrhosis and face a great risk of mortality than NAFL patients or general people. Therefore, in treating a patient with suspected NAFLD, it is of great importance to confirm the diagnosis of fat accumulation using image or histological evidence first with secondary factors of fat accumulation in liver (excessive alcohol consumption, hepatitis C, medication, congenital disease, etc.) duly excluded. Once NAFLD is confirmed, a comprehensive and individualized assessment, including liver decompensation and aminotransferases, is needed. In this article, the results of our overall review of related recent studies are presented to help facilitate accurate dignosis, comprehensive assessment, and proper treatment of NAFLD.