Concentrations of free gamma-aminobutyric acid, other neuroactive amino acids and related compounds were determined in CSF of 42 patients with ischemic stroke, 8 patients with vascular encephalopathy and 14 patients with neurological syndromes of spine degenerative disorders. CSF levels of amino acids were obtained by isocratic HPLC with electrochemical detection after precolumn derivatization. The results obtained indicate that the correlations between assay compounds alter, absolute amounts of their content being unchanged.