A case of subglottic stenosis, recalcitrant to conventional therapy, was associated with asymptomatic aspiration of gastric acid into the larynx. Once the reflux was controlled by use of an antacid regimen and an H2 blocker, the subglottic stenosis resolved and the patient could be decannulated. This case led to the use of an experimental canine model of subglottic stenosis to examine gastric acid as a pathogenic factor in the development of subglottic stenosis. In control animals, mucosal lesions healed without development of stenosis. In experimental animals with mucosal lesions painted with gastric acid, subglottic stenosis developed. When perichondrium and cartilage were violated and gastric acid applied, stenosis was even more severe and developed more rapidly.