The aim of this study was to determine if patients who experience heartburn but have no objective evidence of gastroesophageal reflux disease are responding appropriately to their symptoms. One hundred and forty patients who had been referred for investigations of heartburn (75 males, 65 females, mean age 48 years) answered an Illness Behavior Questionnaire. All patients underwent pH monitoring tests, and endoscopy results were obtained for 119 patients. There was objective evidence of reflux disease on endoscopy or pH monitoring in 105 patients and no objective evidence of reflux in 35 patients. Sixty-six patients were endoscopy-'positive' while 53 patients were endoscopy-'negative'. The Illness Behavior Questionnaires for the four groups were analysed for seven scales of illness behavior and these were compared with reference populations. Patients with heartburn but no objective reflux were similar to those with heartburn and objective reflux on all scales of the Illness Behavior Questionnaire. The reflux group without endoscopic esophagitis also responded to their symptoms in the same way as those with endoscopic esophagitis. It is concluded that a patient's perception of symptoms in gastroesophageal reflux is probably not related to the degree of esophageal mucosal damage.