Patients with familial hypercholesterolemia have a high incidence of coronary heart disease due to diet- and drug-resistant, elevated low-density lipoprotein cholesterol (LDL-C). Five patients with familial hypercholesterolemia and diet- and drug-resistant LDL-C greater than 230 mg/dl were treated by LDL apheresis using dextran sulfate cellulose adsorption (Liposorber System LA-15, Kaneka). Plasma separation was by 0.5-m2 polysulfone hollow fiber filter. Two columns containing 150 ml of dextran sulfate cellulose alternately adsorbed LDL and were regenerated by 4.1% saline. The five patients received a total of 360 treatments at 7-day intervals. The treated plasma volume per session was 4.1 +/- 0.4 l. Postapheresis values compared with preapheresis were: total cholesterol, 40%; LDL-C, 28%; VLDL-C, 65%; HDL-C, 95%; triglycerides, 70%; white blood cells, 116%; platelets, 87%; C3 complement, 79%; fibrinogen, 64%; albumin, 94%. The decrease in HDL-C per treatment was not significant. The safety parameters showed only slight changes. The initial LDL of 436 +/- 172 mg/dl decreased to mean pre-apheresis levels of between 150 and 100 mg/dl. The anti-atherogenic HDL increased in three and remained unchanged in two patients. Adverse events like hypotension, angina pectoris, and technical problems occurred in 11 of the 360 treatments. Long-term treatment of patients with diet- and drug-resistant familial hypercholesterolemia by extracorporeal dextran sulfate cellulose adsorption is effective and safe.