Of 28 patients with severe asthma routinely examined with upper gastrointestinal (UGI) x-ray films, 18 (64%) were found to have hiatus hernia and 13 (46%) were found to have demonstrable gastroesophageal reflux. These prevalences differed significantly (P less than .001) from those seen in a control population (19% and 5%, respectively). These data suggest that aspiration of gastric acid is a frequent incitant to severe asthma and that it should be routinely sought in the treatment-resistant asthmatic patient. Intensive medical regimens directed against reflux and acidity may bring notable improvement in asthma symptoms. Surgical restoration of effective lower esophageal spincter function has proved to be curative in other reported studies.