Bile reflux mto the stomach and then subsequently into the oesophagus occurs frequently after the two basic forms of partial gastrectomy Billroth I and Billroth II. Similarly bile reflux follows the different operations performed to compensate for the temporary slowing of gastric emptying after a vagotomy—Hemeke-Mikulicz pyloroplasty, Finney pyloroplasty and gastrojejunoslomy. When large amounts of bile enter the stomach, after a Billroth II partial gastrectomy for example, bilious vomiting occurs. In the early days of gastric surgery there were several attempts at altering the techniques of the original partial gastrectomy to reduce bile reflux, but another method was to divert bile away from the stomach by a Roux en Y anastomosis (Fig. 1), an end-to-side jejunojejunostomy, which was successful for gross bile vomiting. The reflux of smaller amounts of bile either into the intact stomach or after different types of pyloroplasty or vagotomy without actual bilious vomiting, can cause symptoms which arise from the stomach or the lower oesophagus. The different techniques available for recognition of this duodenogastric reflux will be discussed. It will then be clear that bile reflux occurs more frequently than has been previously thought and that bilious vomiting represents the most extreme form of reflux, with many other symptoms of lesser amounts of reflux being unrecognized. Not all patients with bile reflux have symptoms, even though there may be histological changes in the mucosa of the stomach and oesophagus. On the other hand there are some patients who have a very sensitive lower oesophageal mucosa with minimal histological changes, in whom all bile must be removed from the stomach before they lose their symptoms. Most patients with gastro-oesophageal reflux disease can be