In a prospective study a barium examination combined with food stimulation was compared with the acid reflux test in 30 consecutive patients with symptoms of gastro-oesophageal reflux. Both methods were further compared with endoscopy and histology. Gastro-oesophageal reflux could be demonstrated by the radiologic examination in 22 patients and by the acid reflux test in 23 patients. By combining the two methods gastro-oesophageal reflux could be demonstrated in 27 patients. Comparing the two methods with symptoms, endoscopy, and histology they seemed to be of equal value. Accordingly, a food-stimulated barium examination is recommended as the first method for demonstrating gastro-oesophageal reflux because it is simple and well-tolerated by the patient.