The possibility of a renal-related side effect from nifedipine has been investigated by comparing the effects on plasma creatinine level of coronary arteriography in two groups of patients: one group treated with nifedipine and the other treated with various drugs but without calcium inhibitor. Results showed a moderate (mean, 13%) but highly significant rise in the 27 patients receiving various drugs but no calcium inhibitor. Plasma creatinine change was not significant (mean, 3%) in the 26 patients treated with nifedipine. In the conditions of this study, this difference could only be related to nifedipine treatment. In conclusion, nifedipine may have exerted a protective effect against radiocontrast media nephrotoxicity, which deserves further investigation.