Pulmonary aspiration of gastric contents during general anesthesia has always been a serious problem. Morbidity and mortality depend on the volume and acidity of the aspirated material. The anesthetic agent itself might affect gastric acid secretion. The effect of halothane (5, 10 and 20 mg/kg intravenously) on HCl secretion and cAMP content of gastric juice in pyloric and cardiac ligated male Sprague-Dawley rats was investigated. Compared with the control group, halothane significantly increased both HCl secretion and cAMP content of gastric juice, but to a lesser degree at the higher doses (p < 0.05).