Fourteen women with severe obesity resistant to previous dietetic measures underwent intestinal bypass using Scott's method. Weight loss ranged from 1-2 kg to 50 kg (mean = 25 kg) but weas unpredictable and varied from patient to patient; most remained obese. The other results of the operation were similar to those already reported. There was a decrease in total plasma cholesterol, while HDL cholesterol remained normal. Calcaemia was in the lower range of normal values; one patient developed severe hypokaliaemia (1.8 mEq); low blood magnesium levels and steatorrhoea were common. Fibrosis of the liver was observed in one patient and probably in another. Five patients were re-operated upon for incisional hernia or intestinal occlusion. Other complications reported in the literature (pulmonary embolism, arthralgias, kidney stones and gall stones) did not occur in this series. Because of these complications we decided to stop using intestinal bypass for the treatment of severe obesity. However, in view of the potential dangers of severe obesity we feel that other surgical techniques, such as Mason's gastric bypass, should be considered in some patients.