['Oxidative stress has been implicated in the development of endothelial damage in hemodialysis (HD). We have assessed the effects of N-acetylcysteine (NAC), a compound with antioxidant effects, on malondialdehyde (MDA), a marker of oxidative stress on lipid peroxidation.', 'A clinical trial was conducted in which 24 chronic HD patients were divided into 2 groups according to gender, age, time on HD and cause of renal failure. The NAC group (n = 12) received 600 mg of NAC twice a day for 30 days. The remaining patients constituted the control group (n = 12). MDA levels were measured pre- and post-dialysis at the beginning of the study (baseline) and on day 30 (30 days).', 'Baseline pre- and post-dialysis MDA levels were not different between both groups and were above normal values. A significant decrease was found in the NAC group when either pre- or post-dialysis MDA levels were compared to the corresponding control group levels on day 30 (pre-dialysis NAC vs control group 3.01 +/- 0.6 vs 4.5 +/- 0.73 micromol/l, p < 0.0001, post-dialysis NAC vs control group 2.76 +/- 0.5 vs 4.39 +/- 0.7 micromol/l, p < 0.0001). Only in the NAC group were pre-dialysis MDA 30-day levels different from pre-dialysis baseline levels (3.01 +/- 0.6 vs 5.07 +/- 1.6 micromol/l, p < 0.002). Post-dialysis MDA 30-day concentrations were significantly lower than post-dialysis MDA baseline levels (2.76 +/- 0.5 vs 4.32 +/- 0.7 micromol/l, p < 0.002) and pre-dialysis MDA 30-day measurements (2.76 +/- 0.5 vs 3.01 +/- 0.6 micromol/l, p < 0.011).'] Does n-acetylcysteine reduce malondialdehyde levels in chronic hemodialysis patients -- a pilot study?