A 37-year-old man presented with an evolving inferior myocardial infarction. Coronary angiography performed within 3 hours after the onset of the pain showed spasm of the right coronary artery and the presence of intracoronary thrombi. After resolution of spasm and the disappearance of thrombi, angiography revealed nearly normal coronary arteries. An ergonovine test was positive when the patient was not taking medication and became negative when he was taking diltiazem. The course was uncomplicated, and after 9 months the patient is free of angina.