The effectiveness of nimodipine and N-acetylcysteine in experimental spinal cord injury was evaluated by measuring tissue lipid peroxidation levels of the damaged spinal cords 1 hour after the injury. We used the clip compression method to produce acute spinal cord injury in 40 female Sprague-Dawley rats were used. The rats were divided into four groups of 10 each. Lipid peroxidation was assessed by measuring the tissue content of malonil dialdehyde (MDA). In group 3, nimodipine, and in group 4, N-acetylcysteine was administered i.p. as a single dose immediately after the injury. The rats were sacrificed 1 hour after clip application. The tissue mean MDA content was 3,992 mu mol MDA/gww in group 1 (sham operated), 10,192 mu mol MDA/gww in group 2 (trauma), 10,449 mu mol MDA/gww in group 3 (nimodipine treatment) and 9,009 mu mol MDA/gww in group 4 (N-acetylcysteine treatment). These results demonstrated that a single dose of nimodipine and N-acetylcysteine had no effect on peroxidation of lipid membranes in the early period of experimental spinal cord injury.