Elevated ALT indicates liver damage and can be caused by a variety of reasons: 1. Viral infections: need to test for the appropriate markers, such as hepatitis A/B/C/E, CMV/EBV. 2. Alcohol: heavy alcohol consumption. 3.Fatty liver: caused by fatty deposits. 4.Drugs: Taken drugs/foods/health products that hurt the liver, etc. 5.Autoimmune disorder: often accompanied by other discomfort. 6.Liver manifestations of other systemic diseases.