Background: Crush syndrome has been described as extensive muscle damage, leading to acute renal failure. The aim of this study was to evaluate the possible role of nitric oxide, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in crush syndrome. Patients and methods: A total of 17 patients suffering from crush syndrome, 7 patients without crush syndrome and 10 healthy controls were enrolled in the study. Plasma nitrate, TNF-alpha, IL-1beta levels and biochemical parameters were measured. Results: All patients with crush syndrome demonstrated acute renal failure. Plasma nitrate levels were elevated significantly in the crush syndrome patients compared with patients without crush syndrome (33.5 +/- 20.1 vs. 15.3 +/- 5 mumol/l, p = 0.014). There was no significant difference in TNF-alpha and IL-1beta levels between control and patient groups. Conclusion: Increased plasma nitrate levels in the crush syndrome may be related either to the elevated production of NO or the diminished excretion of nitrate or both. (C) 2002 Elsevier Science B.V. All rights reserved.