The technique of gastroesophageal scintigraphy was developed in order to quantitatively detect reflux from the stomach into the esophagus. The scintigraphic technique was compared to previous diagnostic tests including barium esophagography, fluoroscopy, endoscopy, esophageal biopsy, the acid perfusion test, esophageal manometry, and the acid reflux test. None of the other techniques is as sensitive as gastroesophageal scintigraphy for the detection of reflux, in comparison to the acid reflux test. Gastroesophageal scintigraphy is able to detect gastroesophageal reflux accurately, rapidly, noninvasively, and more sensitively than other diagnostic techniques. In addition, it is able to be employed to quantitate reflux and is suitable for studying the effects of various therapeutic modalities.