The liver is involved in many synthetic and metabolic functions. It takes part in the regulation of circulation, thermoregulation, and digestion. All liver functions are disturbed during harvesting, preservation, and transplantation. The assessment of graft function is still a matter of concern. Many methods including analysis of hepatic enzymes, ketone body ratio, and level of drug metabolites do not give complete and reliable information on graft function. Liver biopsy is still the best diagnostic tool, however, it is invasive, carrying the risk of complications. High-resolution proton spectroscopy of nuclear magnetic resonance was used for analysis of the bile sample obtained from a patient after orthotopic liver transplantation.