Background: Mid-term and long-term clinical outcomes of angiographically documented vasospastic angina following classical antianginal medication is known to be favorable but the adequate duration of medical therapy and their efficacy with the time are varying among previous reports. Methods: A total 158 pts (91 men, Age; 54.0짹11.5 years) without significant coronary stenosis underwent incremental intracoronary acetylcholine (Ach) provocation test (A1 to A3, 20, 50 and 100關g). Pts with documented vasospasm were treated with conventional antianginal medications up to 6 months and discontinued if pts are completely angina-free state and clinically followed without medication. Pts responses were classified as clinical success, recurrent and failure after discontinuation of medication at 6 to 8 months. Results: Baseline characteristics were similar among groups. Most pts received diltiazem (n=139), nitrate (n=58) and/or nicorandil (n=85) and mean number of medications for each pts were 2.18짹0.9. However, 5.8% (8/139) of pts were not able to continue diltiazem due to allergic skin reaction and replaced with nifedipine SR (Adalat짰). Nearly half of enrolled of pts (78/158, 49.4%) were angina-free at 6 months medication (Clinical Success Group). However, one-fourth (26/158, 16.5%) showed recurrence within a month (Recurrent Group). One-third of the pts (54/158, 34.2%) had persistent angina and could not discontinue medication at 6 months (Clinical Failure Group). Although initial success rate (104/158, 65.8%) was higher, limited number of pts remained as clinical success group. There were no death, myocardial infarction and revascularization up to 1 year. Conclusion: Six month angina-free clinical success rate after classical antianginal medication in vasospastic angina was 49% only, recurrent rate after initial success was 16.5% and clinical failure rate was 34.2%. Selective pts with good responder to medication at 6 months may show good prognosis despite the possibility of recurrences. Special cautions should be exercised for the pts who are belong to recurrent and clinical failure group at 6 months.