The jejunoileal bypass for the treatment of extreme obesity is being increasingly criticized because of its severe metabolic complications. With the gastric bypass, developed by Mason in 1967, there now exists an operative alternative that is equivalent concerning weight reduction, but does not create such non-physiologic conditions of absorption, and therefore is not burdened with the severe metabolic disturbances of the jejunoileal bypass. Therefore the jejunoileal bypass should not be used any longer for the treatment of obesity.