This study was conducted retrospectively to elucidate whether the long-term use of nifedipine is effective against the progression of coronary atherosclerosis in humans. Twenty-nine subjects with ischemic heart disease, on whom repeated coronary angiographic examinations (CAG) were performed, were randomly selected. Sixteen subjects were on nifedipine therapy (40 mg/day; NIF group, age 53 +/- 2) and 13 subjects not on nifedipine therapy served as the control group (C group, age 58 +/- 3). No significant differences were observed in clinical backgrounds, including the interval between CAG, between the 2 groups. The lesions with 25 to 75% stenosis on the first CAG were defined as the regions of interest (ROI), and the magnitude of stenosis was quantitatively measured by videodensitometry for each ROI on the first and the second CAG. The magnitude of stenosis showed a small increase (54.1 +/- 2.6 to 58.6 +/- 3.3%: N.S.) for 37 ROIs in the C group. In contrast, it showed a significant decrease (52.5 +/- 3.8 to 46.2 +/- 4.3%: p less than 0.05) for 33 ROIs in the NIF group. The trend was more apparent in the left coronary artery. The change in the mean value for ROIs in each subject produced similar results. These results suggest that the long-term use of nifedipine might be effective in retarding the progression of coronary atherosclerosis in humans. However, a prospective study should be performed to confirm this.