The objective of this study was to examine the suppressive effect of nifedipine on intramural coronary arterial lesions in cholesterol-fed rabbits. Each rabbit in Groups A (n=6) and B (n=5) was fed a 0.3% cholesterol diet and was orally administered nifedipine (40 mg/day) or placebo. Each rabbit in Groups C (n=5) and D (n=6) was fed a 0.5% cholesterol diet and was orally administered nifedipine (40 mg/day) or placebo. The serum concentrations of total cholesterol (TC) were determined at 1-week intervals to calculate the integrated values. The lesion induction ratio was defined as the ratio of intramural coronary arteries 50-150 microm in diameter with arterial lipoidosis to the total number of arteries of the same diameter. There were no significant differences between the nifedipine-treated and placebo groups in either the integrated TC or lesion induction ratio in either the 0.3% and 0.5% cholesterol-fed rabbits. This study demonstrates that nifedipine does not suppress atherogenesis in the intramural small coronary arteries of cholesterol-fed rabbits.