Gagging represents a management problem during dental procedures. A controlled, double blind experiment on human volunteers evaluated the efficacy of nitrous oxide for suppressing experimentally-induced gagging. The ability of the subjects to tolerate palatal and oropharyngeal stimulation was evaluated by measuring the distance of the anatomic palatal and oropharyngeal structure which produce gagging. It was observed that under N(2)O/O(2) inhalation subjects tolerated a significantly more intrusive (deeper) oropharyngeal stimulation than under control conditions.