Purpose: Both parenteral and enteral glutamine have shown beneficial effects in sepsis and ischemia/reperfusion-induced acute lung injury (ALI). Oleic acid (OA) has been used to induce ALI in experimental studies. In this study, we investigated the effects of pretreatment of a bolus dose of enteral glutamine on ALI induced by OA in rats. Methods: Twenty-eight adult female Sprague-Dawley rats weighing 240-300 g were divided into four groups, 7 in each. Group I and group II received normal saline for 30 days, group III and group IV received glutamine at a dose of 1 g/kg for 10 days by gavage, and in group II and group IV 100 mg/kg OA was administered i.v. Histopathological examination of the lung was performed with light and electron microscopy. Levels of protein carbonyl, malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase levels were measured in tissue samples. Levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and total tissue oxidant status and total tissue antioxidant status were measured in serum samples. Results: Light microscopy showed that the total lung injury score of group IV was significantly lower than group II. Change in thickness of the fused basal lamina was not significantly different in groups II and IV under electron microscopy. TNF-α, IL-6, and IL-10 serum levels were higher in group II when compared to group I and significantly attenuated in group IV. Conclusion: Pretreatment with a bolus dose of enteral glutamine minimized the extent of ALI induced by OA in rats. © 2013 Japanese Society of Anesthesiologists.