In order to assess if the use of the laryngeal mask airway is associated with an increased risk of gastric regurgitation during mechanical ventilation, we studied 50 patients allocated randomly to undergo anaesthesia with either artificial ventilation with isoflurane and nitrous oxide in oxygen and atracurium (group A) or spontaneous ventilation with isoflurane and nitrous oxide in oxygen (group B). In both groups a laryngeal mask airway was used. Regurgitation was assessed by the patient ingesting a methylene blue capsule 10 min before induction of anaesthesia and examining the oropharynx by direct laryngoscopy at the end of surgery. In one patient in each group, there was staining of the oropharynx with blue dye at the end of surgery. In the patient in group A, dye was present in the trachea and bronchi.