Ergot preparations produce coronary artery spasm in a high percentage of patients who have variant angina diagnosed on clinical and electrocardiographic grounds. Positive results are very uncommon in other groups of patients with coronary artery disease. Other studies show that ergot provocation tests do not help clinicians to choose the correct therapy in angina. Several studies have shown that these tests have a significant incidence of complications and that some of these are serious. Both myocardial infarction and death have been described as occurring as a direct result of ergot provocation tests. Therefore, ergot provocation tests do not often produce useful clinical information and carry definite and severe risks.