The clinical manifestations of symptomatic coronary arterial spasm were analyzed in 30 patients whose coronary arteriograms demonstrated no fixed severe obstructions. The study group consisted of 14 men and 16 women (average age, 47 years). Angina at rest was invariable and it was usually typical in quality, location, duration and response to nitroglycerin. Exertional angina occurred in 23 percent and syncope with angina in 33 percent. Spontaneous remission of angina for at least 1 month occurred in 57 percent of patients. Prinzmetal's variant angina occurred in 77 percent of patients and only S-T segment depression or T wave changes during angina occurred in 23 percent. Major arrhythmias during ischemia developed in 47 percent. Exericse tests were positive in 24 percent. Myocardial infarction, probably due to coronary spasm, occurred in 7 percent of patients. Isosorbide dinitrate and propranolol were effective therapy in only 39 percent and 6 percent of patients, respectively. Nifedipine, a calcium flux antagonist, was effective in 80 percent of patients. Patients with normal coronary arteriograms who have clinical features suggestive of coronary arterial spasm should be considered for further investigation, including long-term electrocardiographic monitoring and provocative testing for spasm.