Ischemia due to transient splanchnic vasoconstriction following major burns causes oxidative and/or nitrosative damage in intestinal tissue followed by reperfusion injury. Thus, burn injury leads to breakdown in the intestinal mucosal barrier which can induce bacterial translocation (BT). As an antioxidant and anti-inflammatory agent the protective effects of N-acetylcysteine (NAC) are documented in several studies. This study was designed to determine the effect of NAC treatment on the oxidative stress in the intestine and BT after burn injury. To evaluate this, 32 Wistar rats were randomly divided into four groups as sham (n = 8), burn (n = 8), pre-burn, NAC injection (150 mg kg -1, intraperitoneally) 15 min before thermal injury (n = 8), post-burn, NAC injection (150 mg kg-1, intraperitoneally) 2 h after thermal injury. Under anesthesia, the shaved dorsal skin of rats was exposed to boiling water for 12 s to induce burn injury in a standardized manner. Twenty-four hours later, tissue samples from mesenteric lymph nodes (MLN), spleen, and liver were obtained under sterile conditions for microbiological analysis and ileum samples were harvested for biochemical analysis. In the burn group, the incidence of isolating bacteria in MLN, spleen, and liver specimens was significantly higher than other groups. NAC treatment prevented burn-induced BT in both pre- and post-burn groups. Thermal injury caused a significant decrease in glutathione (GSH) level, significant increases in malondialdehyde (MDA) and myeloperoxidase (MPO) activity at post-burn 24th hour. Treatment of rats with NAC significantly elevated the reduced GSH levels while decreasing MDA levels and MPO activity. These data suggested that NAC has a crucial cytoprotective role in intestinal mucosal barrier and preventive effects against burn injury-induced BT. © 2004 Elsevier Ltd and ISBI. All rights reserved.