We assayed serum levels of certain enzymes and tumor markers in patients after transcatheter arterial embolization (TAE) to evaluate the effectiveness of this treatment. Twenty patients had hepatocellular carcinoma and two patients had metastases to the liver from colon cancer. Assays were first done immediately after TAE and were continued for the next 12 days. Glutamic oxaloacetic transaminase (GOT; EC 2.6.1.1, L-aspartate:2-oxoglutarate aminotransferase), glutamic pyruvic transaminase (GPT; EC 2.6.1.2, L-alanine:2-oxoglutarate aminotransferase), and lactate dehydrogenase (EC 1.1.1.27; (S)-lactate:NAD+ oxidoreductase) peaked 24 to 48 h after TAE and returned to the base lines in 7 to 10 days. Mitochondrial GOT (mGOT) and glutamate dehydrogenase (GLDH; EC 1.4.1.2, L-glutamate:NAD+ oxidoreductase) also peaked at the same time after TAE. alpha-Fetoprotein peaked 2 h after TAE and decreased to half of the baseline on day 7. Carcinoembryonic antigen peaked at 24 h and fell at 48 h only in the patients with colon cancer. The total amount of cytosolic GOT, GPT, mGOT, and GLDH released was correlated to the volume of the necrotic mass estimated by computed tomography scans. The correlation coefficients for mGOT and GLDH were r = 0.919 and r = 0.939 (both p less than 0.001), respectively. Assays of mGOT and GLDH may be useful to estimate the volume of the necrotic mass of a hepatoma or metastatic carcinoma in the liver.