There a many different reasons for elevation in AST and ALT. AST comes from multiple different sources, especially muscle. ALT is more specific to the liver. Elevation of both is highly suggestive of liver injury. -Any type of liver disease (Fatty liver disease, viral hepatitis, hemochromatosis, cirrhosis, Wilson s disease, etc) -Alcohol abuse -drugs (tylenol, statins, NSAIDs, ACEi, heparin, etc) -hepatic congestion in heart or liver failure -viral illness such as mono -heart attacks -severe muscle trauma Your history sounds most likely that AST and ALT are elevated by your cholesterol medication. AST/ALT levels in the thousands are often indicative of viral hepatitis. You can continue to taking your cholesterol medication if the AST and ALT are not 3 times the upper limits of normal (which is about 100). Often the elevations will resolve spontaneously. Coexisting elevations of transaminase levels from non alcoholic fatty liver disease and stable hepatitis B and C viral infections are not contraindications to statin use. You should have you liver investigated more if these enzymes continue to be elevated in future lab work. Liver function test include PT/INR, Albumin, and Bilirubin. You should also see your primary care doctor if you develop right upper quadrant abdominal pain.