Seventy-seven hypercholesterolemic patients participated in a 26-week, multicenter, randomized, double-blind, placebo-controlled study that investigated the efficacy and safety of pravastatin therapy. All patients had primary moderate hypercholesterolemia (total cholesterol 200-300 mg/dl, at the end of a 6-week dietary run-in period) and two additional coronary risk factors. Pravastatin, 20-40 mg/day given at bedtime, reduced total cholesterol by 19-22%, LDL-cholesterol by 24-30%, triglycerides by 10-30% and increased HDL-cholesterol by 9-13%. The drug caused mild elevation in alanine aminotransferase and aspartate aminotransferase. Almost all these elevations were within normal limits and no patient was clinically symptomatic. No other significant differences were observed between the pravastatin and the placebo-treated groups with regard to other adverse effects and to patient compliance and withdrawal. It is concluded that pravastatin has a beneficial effect on the lipid profile and that the drug is safe and well tolerated.