Reflux of upper intestinal content to the gastric remnant after gastric resection is common and may cause damage to the gastric mucosa, resulting in gastritis, gastric ulcer, and possibly dysplasia. Different surgical procedures have been proposed to prevent reflux, among them Roux-en-Y diversion. In this study we have compared antrectomy followed by gastroduodenostomy (BI) with antrectomy followed by Roux-en-Y anastomosis with regard to enterogastric reflux. Reflux was recorded by cholescintigraphy, using a new method for quantification. In all patients biopsy specimens were taken for histopathological evaluation at gastroscopy. Twenty-seven patients were studied, 11 with gastroduodenostomy and 16 with Roux-en-Y diversion. All patients in the gastroduodenostomy group had reflux, compared with four in the Roux group (p less than 0.001). Under the light microscope all patients in the BI group showed a moderate to severe degree of inflammation compared with only seven in the Roux-en-Y group (p = 0.028). Our results show that Roux-en-Y drainage effectively diminishes reflux and may be an explanation for the lower extent of mucosal damage in these patients.