It is not clear why some patients with aspiration advance to acute lung injury or acute respiratory distress syndrome, whereas others do not. The Western diet is high in advanced glycation end-products (AGEs), which have been found to be proinflammatory. We hypothesize that dietary AGEs exaggerate the pulmonary inflammatory response following gastric aspiration. CD-1 mice were randomized to receive either a low-AGE (LAGE) or a high-AGE (HAGE) diet for 4 weeks. Five hours after intratracheal instillation of acidified small gastric particles, pulmonary function was determined. Polymorphonuclear neutrophil counts, albumin, cytokine/chemokine, and tumor necrosis factor soluble receptor II concentrations in the bronchoalveolar lavage and lung myeloperoxidase activity were measured. Compared with LAGE-fed animals, those fed a HAGE diet had increased lung tissue resistance (P = 0.017), bronchoalveolar lavage albumin concentration (P < 0.05), pulmonary polymorphonuclear neutrophil counts (P = 0.0045), and lung myeloperoxidase activity (P = 0.002) following aspiration. In addition, the plasma levels of tumor necrosis factor soluble receptor II were significantly elevated (P < 0.05), whereas paradoxically levels of keratinocyte chemoattractant and monocyte chemoattractant protein 1 were decreased in mice with HAGE diet. In conclusion, a diet high in AGEs exacerbates acute lung injury following gastric aspiration as evidenced by increases in neutrophil infiltration, airway albumin leakage, and decreased pulmonary compliance. This is the first evidence implicating exacerbation of acute inflammatory lung injury by dietary AGEs. Targeting AGEs in the circulatory system may offer a therapeutic strategy for limiting lung injury following gastric aspiration.