LDL-apheresis lowers the LDL level in patients with severe hypercholesterolemia. The present study compared three apheresis methods--DSA, DALI, and plasma exchange--for effectiveness in removal of LDL and effect on various blood parameters involved in atherogenesis. The study group included 6 patients with primary hypercholesterolemia unresponsive to maximal drug therapy. All were treated first with 4 consecutive plasma exchange sessions followed by 4 DSA sessions; in four out of six, an additional 4 sessions of DALI were then performed. Levels of lipoproteins, apoproteins, CRP, homocysteine, fibrinogen, and blood count were determined before and after each session. All 3 procedures yielded a significant reduction in total cholesterol and ApoB-containing lipoproteins, with DALI being the most effective. Also, a significant reduction in triglycerides, HDL, and ApoA1 was observed with all the methods. The reduction in HDL-C with DSA and DALI was greater than previously reported. The LDL/HDL-cholesterol ratio decreased significantly with DSA and DALI and increased with plasma exchange. There was a significant decrease in CRP, fibrinogen, and platelets with all three methods, and a significant decrease in homocysteine only with DSA and DALI. All three procedures effectively reduced the concentration of various compounds involved in atherosclerosis. Plasma exchange is nonselective and cannot be recommended as the procedure of choice.