The favourable results obtained from a fat-reduced diet during metabolic ward conditions in patients with ileal dysfunction persisted during continued dietary treatment outside the hospital. The observation period for 10 patients was 3–27 months (mean 14 months) ended by a short-time study at a metabolic ward. According to our findings, the daily fat intake should be limited to not more than 50 g. In spite of a reduction of energy with this diet, the patients (with one exception) did not loose weight and many of them increased their total body potassium. The general outline for the fat-reduced diet isgive