10 Patients with primary hypercholesterolemia were treated for 12 weeks with lovastation(20mg t.i.d). Lovastatin reduced mean total and low density lipoprotein cholesterol by 43% and 57% respectively(p<0.001). High density lipoprotein cholesterol and triglyceride levels were unchanged by the drug. Adverse effects attributable to lovastatin were not observed. Thus lovastatin is considered as an effective lipid lowering agent for the treatment of primary moderate hypercholesterolemia.