Background This small study has determined the effect of vitamin Con myocardial reperfusion inpatients undergoing elective percutaneous coronary intervention (PCI).This study was to explore whether antioxidant vitamin C infusion before the procedure is able to affect the incidence of periprocedural myocardialinjury (PMI) in patients undergoing PCI.Methods In this prospective single-centre randomized study, 532 patients were randomized into 2 groups: the vitamin C group, which received a 3-g vitamin C infusion within 6 hours before PCI, and a control group, which received normal saline.The primary end point was the troponin I-defined PMI, and the second end point was the creatine kinase (CK)-MB-defined PMI.Separate analyses using both end points were performed.PMI was defined as an elevation of cardiac biomarker values (CK-MB or troponin Ⅰ) > 5 times the upper limit of normal (ULN), alone or associated with chest pain or ST-segment or T-wave changes.Results After PCI, the incidence of PMI was reduced, whether defined by troponin or by CK-MB, compared with the control group (troponin Ⅰ, 10.9% vs 18.4%; P =0.016; CK-MB, 4.2% vs 8.6%; P =0.035).Logistic multivariate analysis showed that preprocedure use of vitamin C is an independent predictor of PMI either defined by troponin Ⅰ (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.33-0.97; P =0.037) or by CK-MB (OR, 0.37; 95% CI, 0.14-0.99; P =0.048).Conclusions In patients undergoing elective PCI, preprocedure intravenous treatment with vitamin C is associated with less myocardial injury.