Administration of methylxanthines may diminish meconium-induced acute lung injury. Meconium-instilled rabbits intravenously received aminophylline (2.0 mg/kg) at two doses 0.5 h and 2.5 h after meconium instillation or were left without treatment, and were oxygen-ventilated for additional 5 h. At the end of experiment, lungs and trachea were excised. Within 5 h after the first dose of treatment, aminophylline significantly improved gas exchange and decreased right-to-left pulmonary shunts, central venous pressure, and ventilatory pressures. Moreover, aminophylline reduced meconium-induced lung edema formation, airway hyperreactivity to histamine, count of neutrophils in bronchoalveolar lavage fluid associated with higher total white blood cells and neutrophils in the blood, and diminished oxidative modifications of proteins and lipids in lung tissue compared with the non-treated meconium-instilled group. In a rabbit model of the meconium aspiration syndrome, aminophylline treatment enhanced pulmonary functions and alleviated oxidative injury and changes in airway reactivity related to lung inflammation.