The authors studied the effects of lovastatin on the parameters of serum and lipoprotein lipids in an open multicenter trial. 160 patients with hypercholesterolemia participated in the study, 151 of whom completed the trial. After a 4 week period of dietary measures, the patients were treated with lovastatin for 12 weeks while combining standard lipid lowering diet. The initial dose of the drug was 20 mg, this was increased until serum cholesterol level decreased under 5.2 mmol/l, or to a maximal daily dose of 80 mg. By the end of the 12th week, serum cholesterol level was reduced by an average of 33% (p < 0.001), LDL-cholesterol by an average of 45% (p < 0.001), serum triglyceride concentration by an average of 22% (p < 0.001) and HDL-cholesterol increased by an average of 13% (p < 0.001). Lovastatin showed a very good safety profile, therapy had to be cancelled due to the occurrence of adverse events only in 4 cases.