Serum glutamic oxalacetic transaminase acitivity is elevated following acute liver cell injury due to toxic, infectious, obstructive, neoplastic and degenerative causes. Apparently the SGO-T activity is an index of liver cell damage and does not necessarily correlate with the usual test of liver dysfunction. Toxic, infectious and homologous serum hepatitis are associated with impressive elevation of SGO-T, and is many times greater than the activity seen in extrahepatic biliary obstruction. SGO-T activity appears to be a sensitive index of liver metastases.