The purpose of the study was to evaluate the efficacy and safety of a new formulation of colestipol provided in table form. This was a randomized, double-blind, placebo-controlled, multicenter, dose-ranging study. A total of 196 patients with primary hypercholesterolemia who were following a low-fat, low-cholesterol diet (NCEP Step I diet), and having mean low-density lipoprotein cholesterol (LDL-C) levels greater-than-or-equal4.14 mmol L(minus sign1) (160 mg dl(minus sign1)) and less-than-or-equal6.46 mmol L(minus sign1) (250 mg dl(minus sign1)) were studied. Study medication was taken twice daily, with breakfast and supper, for 8 weeks. The five parallel treatment groups consisted of colestipol tablets 1, 2, 4, and 8 g BID, and matching placebo tablets BID. The main outcome measures were absolute change and percent change from baseline in selected lipid, lipoprotein, and apolipoprotein measurements; LDL-C was considered primary. Statistically significant (p less-than-or-equal 0.05) dose-dependent reductions in LDL-C from 5.2% to 25.8% and in total cholesterol from 2.8% to 16.8% were observed. Colestipol tablet treatment also resulted in statistically significant dose-dependent increases in LpAl levels reaching 25.8% at 16 g day(minus sign1). The treatment was well tolerated, and no serious adverse events were reported. Colestipol administered in tablet form was efficacious in lowering LDL-C and total cholesterol and was well tolerated in patients with primary hypercholesterolemia.