To evaluate the effects of defibrase on thrombosis after coronary intervention. 12 dogs were randomized into group to be treated with defibrase (n = 6) and another group with heparin (n = 6) after coronary intervention. After implanting stents in coronary arteries, canine platelets labeled with 99mTc-hexamethyl propylene amine oxime were re-transfused into blood circulation. The stenting vessels were imaged with gamma-camera in vivo and in vitro at the 4th and 24th hour, then the relative radioactivity of stenting vessels was quantified. The isolated stenting vessels were weighted and measured with gamma-counter and the number of deposited platelets was calculated. The relative radioactivity and the number of deposited platelets were lower in the group of defibrase than in the group of heparin (P < 0.01). Compared with heparin, defibrase has more potent effect on the prevention of thrombus formation and may reduce the early-reocclusion after coronary intervention.