The metabolic state of the liver during preservation as well as in and after auxiliary transplantation was investigated in dogs. The biopsy was carried out by means of TRU-CUT biopsy needle. - The ATP concentration, the storage of energy, the amount of the adenine nucleotides, and the ATP/ADP quotient decrease in the preserved liver. The AMP concentration, the concentration of the hexosemonophosphates and the mass-effective quotient of the phosphofructokinase increase simultaneously. The energy supply is the glycolysis exclusively. A lactate accumulation is avoided by continuous perfusion. - The changeover of the anaerobic to the aerobic energy preparation took place by degrees after the recovery of the liver circulation. The ATP concentration, the ATP/ADP quotient, the storage of energy, and the amount of the adenine nucleotides increase in the transplanted liver. - An irreversible ischemic damage of the liver appears in the metabolic state of the organ by a massive decrease of the ATP concentration below 0.7 mmol/kg, the amount of the adenine nucleotides below 1.8 mmol/kg, and AMP concentration.