Thirty-seven patients with coronary artery spasm and minor coronary atherosclerosis (34) or normal coronary arteries (3) were followed up long-term. All had angina at rest, 32 had nocturnal angina, and 13 had a positive exercise test with S-T elevation. Three had a previous subendocardial infarction; 10 had had serious arrhythmias, which caused syncope in 7. At last review, 21 months (range 1 to 61) after starting therapy, 27 patients continued on verapamil, 314 (120 to 600) mg/day; 4 who did not respond to verapamil were taking nifedipine, 58 (30 to 80) mg/day; and 16 were also taking isosorbide dinitrate, 41 (20 to 80) mg/day. Of the 31 patients on therapy, 21 were asymptomatic, 9 were improved (1 to 4 attacks/month), and 1 had an average of 8 anginal attacks/month; the remaining 6 had stopped therapy and 5 were asymptomatic a mean of 10 (3 to 18) months after stopping. The exercise test became negative in all 12 patients tested on therapy, although 3 required nitrates in addition to verapamil or nifedipine. In 26 supervised treatment withdrawals in the hospital, a mean of 15 (1 to 55) months on therapy, 10 developed angina in less than 48 hours. Angina recurred in all 6 unsupervised, patient-initiated withdrawals. Failure to stop smoking was positively associated with recurrence of angina on treatment withdrawal (p less than 0.02). Long-term treatment of coronary artery spasm with verapamil or nifedipine together with isosorbide dinitrate was well tolerated and effectively relieved angina. No documented serious arrhythmias, syncopal episodes, myocardial infarction, or death occurred during follow-up.