The authors report 4 cases of hyperlipemia and show the great benefit which results from ileal exclusion when there is an atherogenic risk. The considerable reduction in total lipid, cholesterol, triglycerides, and prebeta-lipoproteins is constant together with clarification of the serum. In one case, angina pectoris regressed considerably, as did arteritis of the lower limbs (unlimited walking became possible, oscillometry in the leg improved from 2 to 7). Surgery is indicated whenever by lack of will power, the diet and medical treatment cannot be followed, when social and economic conditions make proper medical treatment impossible, or when the latter has failed. The existence of arterial lesions, cardiac or cerebral complications makes surgery even more urgent. Gall-stones were observed in gall bladder. The authors raise the problem of oxalate stones. Only type II familial hyperlipemia in homozygotes should be excluded: and end-to-side portacaval anastomosis seems to be preferable.