In this study we examined the influence of different lipid lowering drugs (xantinolnicotinate (Xn), bezafibrate (Bf) and a combination of inositolnicotinate and clofibrate (In-Cl)) on the lipid and lipoprotein concentration in 61 hyperlipidemics of the types IIb, IV and V. Treatment with the 3 drugs showed a significant LDL-cholesterol decrease in type IIb and a LDL-cholesterol increase in the types IV and V. Concerning protective HDL lipoproteins an increase of HDL-cholesterol could be observed in all three types only by treatment with xantinolnicotinate and bezafibrate. Concomitantly in type V a type conversion to type IV could be observed under drug treatment regarding the chemical composition of the lipoprotein fractions VLDL, LDL and HDL.