For the first time the intracellular concentrations of N-acetylaspartate (NAA), aspartate (Asp), and glutamate (Glu) were measured in human brain in vivo, and the effect of severe traumatic brain injury on NAA synthesis in acute and remote posttraumatic phases was revealed. In non-damaged (MRI-negative) lobes the next day after injury, Asp and Glu decreased by 45% and 35%, respectively, while NAA decreased only by 16%. A negative correlation between NAA and Asp/Glu ratio was found. The Glu level returned to the norm long after injury, Asp remained below the norm by 60%, NAA decreased by 65% relative to the norm, and Asp/Glu decreased significantly. The results obtained educe the leading role of neuronal aspartate-malate shuttle in NAA synthesis alterations.