Background: alpha-lipoic acid has antioxidant effect, anti-inflammatory effect. High dose alpha-lipoic acid may attenuate in-stent restenosis(ISR) by reducing stent induced inflammation. We evaluated the clinical outcomes, angiographic results of patients taking low dose alpha-lipoic acid after PCI with bare metal stent(BMS). Methods: This study was a single center, prospective randomized study. The study population currently included 127 patients with coronary artery disease, assigned to 67 patients taking 600mg of low dose alpha-lipoic acid daily in addition to anti-anginal medications and 60 patients without alpha-lipoic acid(control group) after index procedure with BMSt. We have analyzed the clinical outcomes, angiographic results and the adverse effects after 6 months of treatment. Our primary outcome was the composite of all-cause death, myocardial infarction(MI), target lesion revascularization(TLR). Secondary endpoint was composed of ISR and angiographic finding. Results: 111 patients (60 in the alpha-lipoic acid group and 51 in the control group) completed follow-up angiography. There were no significant differences between the alpha-lipoic acid group and the control group of the baseline clinical demographics and angiographic findings. The average lesion length and reference diameter (RD) were 20.6짹4.1 mm vs. 20.6짹5.5 mm (p=0.961) and 2.76짹0.54 mm vs. 2.94짹0.66 mm (p=0.119) in the alpha-lipoic acid group and the control group, respectively. After 6 months of medication, there was no difference of major cardiac adverse events (MACE), TLR and the rate of ISR between two groups. (MACE 8/67, 11.9% vs. 8/60, 13.3%, p=0.511, TLR 8/67, 11.9% vs. 8/60, 13.3%, p=0.511, ISR 12/60, 20.0% vs. 12/51, 23.5%, p=0.817). Conclusion: The results of this study showed that low dose alpha lipoic acid in patients who underwent PCI, was not associated with reduced MACE, TLR and restenosis.