Regurgitation of bile into the stomach after gastric surgery often causes severe and distressing symptoms, though the onset may be delayed for some years. We have used a Roux loop diversion as a secondary procedure for bile reflux in 36 patients, making the anastomosis from 18 to 40 cm below the stomach. There were no deaths and the clinical results were good in 20 of 27 patients followed up from 1 to 10 years. Vagotomy was omitted in 13 patients, 2 of whom subsequently developed jejunal ulceration. One patient developed an unexplained gastric ulcer and 2 operations failed because the loop was too short. The optimum length may well be 40 cm and vagotomy should be added in all cases. In 3 patients with associated dumping the upper 10 cm of the Roux loop was reversed.