Background hsCRP level is known to be a strong risk factor for future cardiovascualr events in patients with coronary artery disease (CAD). We investigated whether the high hsCRP level can adversely impact on the coronary artery spasm (CAS) by intracoronary acetylcholine (Ach) provocation test. Methods A total 1142 consecutive patients without significant CAD who underwent the Ach provocation test by injecting incremental doses of 20, 50, 100 ug into the left coronary artery between March 2004 and April 2009. Significant CAS was defined as focal or diffuse severe transient luminal narrowing (>70%) with/without chest pain or ST-T change on ECG. The Ach provocation test results and its associated parameters were compared between the high hsCRP group (>2mg/L, n=216) and control group (n=926). Results The clinical and angiographic characteristics were similar between two groups. After Ach injection, the rate of positive provocation test result, ischemic ST-T change and diffuse spasm were higher in high hsCRP group. There was a trend toward higher incidence of more severe spasm in high hsCRP group (Table). Multivariate logistic analysis showed that high hsCRP was an independent risk factor for Ach-induced CAS (odd ratio; 1.32, 95% confidence interval; 1.00-1.74, p=0.049). Conclusion In our study, high hsCRP level was an independent predictor for significant CAS as assessed with the intracoronary Ach provocation test and was associated with diffuse and severe CAS