We tested the effects of the nitric oxide donor nitroprusside as treatment for no reflow in 23 consecutive patients who underwent coronary angioplasty for acute myocardial infarction. No reflow was defined as a decrease of >/=1 Thrombolysis In Myocardial Infarction (TIMI) trial flow grade occurring after successful initial coronary recanalization. Nitroprusside induced a significant improvement in coronary flow, with an increase in TIMI flow grade from 1.5 +/- 0.8 to 2.9 +/- 0.3 (p <0.0001) and in TIMI frame count from 46 +/- 25 to 16 +/- 5 (p <0.0001). There were no significant adverse effects apart from transient hypotension. Intracoronary nitroprusside should be considered as a treatment of no reflow occurring in acute myocardial infarction.