Selective infusion of the epinephrine into the renal artery has been used in the field of the diagnostic and the therapeutic raidology for correct diagnosis and effective treatment, respectively. However, administration of overdose of epiniphrine may cause serious complication, renal infarction. The study was undertaken to evaluated the sequetial change of renal arterial constrictive effect of selective infusion of epiniphrine into renal artery and to determine the critical doses of epiniphrine producting irreversible renal infarct, A total of 25 rabbits are used, which are divided into 5 groups. Under the general anesthesia is made the selective infusion of various doses of epiniphrine into the right renal artery of the rabbits. At the various time interval during and after the epinephrine infusion, renal angiography was done, and 24 hrs. later, gross and microscopic findings of the kidney were observed. The results are as follows : 1. Vasoconstriction of renal artery occur ed within 2 mins, infusion, and maxmum effect within 5 mins. 2. It seems that there is correlation between the amount of infused epinephrine and the time takned to recover form constriction of renal artery. 3. When epinephrine infused into the renal artery in the rate of 1 ug/min ,, renal infarct is not noticed below the level of 10 mins. But correlation between the amount of infused epiniphrine and the frequency of renal infarct occurs above 20 mins, infusion.