The causes of high gamma-glutamyltransferase are categorized as liver disease, biliary tract obstructive disease, and other factors. 1. Liver diseases: Alcoholic liver disease, non-alcoholic fatty liver disease and other liver diseases can cause moderate elevation of γ-glutamyltransferase, and if there is a persistent elevation, it means that the condition may be deteriorating. 2. Biliary tract obstructive diseases: biliary tract obstructive diseases such as sclerosing cholangitis can lead to chronic accumulation of bile, so that the γ-glutamyl transferase discharge is blocked, and with the bile reflux into the bloodstream, resulting in an abnormal increase in serum γ-glutamyl transferase. In addition, pancreatitis, pancreatic tumors, prostate tumors and other diseases may also cause a mild increase in γ-glutamyltransferase, so when you find that the index is elevated, you should seek medical attention as soon as possible, under the guidance of the doctor for targeted treatment.