Proton magnetic resonance (MR) spectroscopy of the brain was performed in 11 patients with chronic hepatic encephalopathy (CHE), and the results were compared with those of patients with liver disease but without CHE; clinical control subjects with diabetes, uremia, or cortical atrophy; and healthy subjects. The technique of water-suppressed stimulated-echo hydrogen-1 MR spectroscopy for detection of cerebral glutamate, glutamine, glucose, N-acetylaspartate, choline metabolites, (phospho)creatine, and myo-inositol is described. Specific changes in the brain of CHE patients included the anticipated elevation in cerebral glutamine levels (P less than or equal to .0001), a 23% reduction in choline metabolite levels (P less than or equal to .0001), and a more than 50% reduction in cerebral myo-inositol levels (P less than or equal to .0001). In four of the 15 patients with liver disease but without clinical CHE, a significant reduction in the myo-inositol level was detected, and in two of these patients an elevation in the glutamine concentration was also observed. These findings indicate a role for image-guided H-1 MR spectroscopy in the diagnosis and monitoring of both overt and preclinical CHE.