The incidence of gastric regurgitation was studied in 138 women during gynecologic operations performed under general endotracheal anesthesia. Laryngoscopy at the conclusion of anesthesia revealed no instance of gross regurgitation. The average pH of secretions suctioned from the pharynx before extubation averaged 5.6 +/- 1.0. Seven of 35 (20%) patients having emergency laparoscopy in the head-down position had pharyngeal contents with pH of 3 or less. Position had no effect in the incidence of highly acid pharyngeal contents in patients having elective surgery, and there was no correlation between pH of pharyngeal contents and age, duration of anesthesia or type of muscle relaxant.