Repeated plasma exchange is an effective treatment for young patients with familial hypercholesterolemia. We treated 2 homozygous and 1 heterozygous patient with very high cholesterol levels with continuous plasma exchange using human albumin solution as exchange medium. The treatment was repeated every 2 weeks in 2 patients and weekly in the third. Treatment periods of plasma exchange alone and of plasma exchange with concomitant drug therapy were compared. For drug treatment beta-pyridylcarbinol, the alcohol corresponding to nicotinic acid (0.9 g/day equivalent to 3 g of nicotinic acid) and cholestyramine (16 g/day) were used. Plasma exchange alone resulted in a decrease of all lipids by 55% and of apolipoproteins by 50-60% as compared to the plasma levels before exchange. Subsequently all lipoproteins rose again to reach pre-exchange levels within about 2 weeks. There was no difference between the homozygous and the heterozygous patients. Beta-pyridylcarbinol or cholestyramine given concomitantly did not alter the post-exchange increase of total, LDL, HDL cholesterol nor of the corresponding apolipoproteins except of apolipoprotein B.