Establishment of a noninvasive diagnostic method to document coronary vasospasm would be useful in the management of the patients with variant angina, especially in the screening of the patients, evaluation of the therapeutic efficacy of the prescribed drugs and determination of the activity of the disease. The present study was performed to clarify the clinical feasibility and diagnostic validity of bedside intravenous ergonovine test and to determine the variables affecting the diagnostic sensitivity of the test. The study group consisted of 59 patients with chest pain in whom diagnostic coronary angiography with intracoronary acetylcholine challenge test for the induction of coronary vasospasm was performed ; 30 patients were proven to have variant angina and 29 patients to have atypical chest pain. Bedside ergonovine test was done one day after the diagnostic coronary angiography and reversible ST segment displacement(elevation or depression) and/or T wave changes in ECG with ergonovine injection was used as the only positive criteria of the test. A bolus of ergonovine maleate(0.025 or 0.050mg) was injected intravenously at 5 minute intervals up to total cumulative dosage of 0.25 mg, and blood pressure and a 12-lead ECG were recorded every 3 minutes after each injection. Intravenous nitroglycerin of 0.25mg was administered for the termination of the test when hypertension(systolic BP>200mmHg), hypotension(systolic BP<90mmHg) or significant arrhythmia was observed. Twenty seven out of 30 patients with variant angina developed chest pain or discomport during the test and among them 22 showed simultaneous reversible ECG changes. In 29 patients with atypical chest pain 11 patients(38%) complained of chest pain or discomport without reversible ECG change during the test, and the overall sensitivity and specificity of the beside ergonovine test were 73% and 100% respectively. The mean cumulative dose of ergonovine which evoked the positive reponse was 117microgram. The patterns of reversible ECG changes of the positive response were variable : 50%(11/22) showed significant ST segment elevation, while ST segment depression(18%) and T wave changes without ST segment displacement(32%) were observed with ergonovine injection. Degree of disease activity of the variant angina, number of spasm-induced vessels and presence of concomitant fixed lesion are important variables affecting the sensitivity of the test. The changes of blood pressure and heart rate were minimal during the test and there was neither significant arrhythmia nor test-related mortality. Thus we concluded that bedside intravenous ergonovine test is a safe, sensitive and highly specific test for coronary vasospasm in selected group of patients with chest pain syndrome. Further study with other methods besides ECG to document myocardial ischemia seems to be necessary for improvement of the sensitivity of bedside ergonovine test.