Objective: The purpose of this study was to determine the level of nitric oxide (NO) metabolites, nitrite and nitrate in human cerebrospinal fluid (CSF) and serum and to assess whether there is any relationship among CSF, serum nitrate-nitrite levels and preeclampsia. Study design: Twenty-one preeclamptic and 27 healthy pregnant women as control group who underwent cesarean section (C/S) were included in the study. Before administering local anesthetic for spinal anesthesia, 2 ml CSF and 4 ml venous blood sample were taken. CSF and serum total nitrite, direct nitrite and nitrate levels were determined spectrophotometrically. Results: CSF total nitrite, direct nitrite and nitrate levels were significantly different between the two groups (21.00 +/- 1.68, 8.28 +/- 0.89 and 12.71 +/- 1.08 mumol/l, respectively versus 15.53 +/- 1.49, 5.57 +/- 0.39 and 9.96 +/- 1.45 mumol/l, respectively, P < 0.05). Significantly higher serum nitrate level was found (31.84 +/- 2.31 mumol/l) in the control group compared to the preeclamptic group serum nitrate level (25.06 +/- 2.02 mumol/l). Statistical comparisons were performed by the Mann-Whitney U-test. Conclusion: CSF-NO is significantly higher but serum NO is lower in preeclamptic group compared with control group may suggest independent regulation of NO in the two compartments. The determination of CSF-NO metabolites could be useful to clarify whether increased NO production is predominantly associated with poor perfusion of the brain in preeclampsia. (C) 2003 Elsevier Ireland Ltd. All rights reserved.