Objective To investigate the influencing factors of adverse drug reactions caused by Yunnan Baiyao Capsules and to promote rational drug use in clinic. Methods Nested case-control study was adopted to collect clinical data and other characteristics of patients for case-control study by taking the patients with severe adverse reactions during centralized monitoring as ″cases″ and the patients without adverse reactions during centralized monitoring as ″controls″. Results Among 906 patients treated with Yunnan Baiyao Capsules,1 case had adverse reactions,the incidence rate was 0. 11%. Conclusion In the cases of Yunnan Baiyao Capsules combined with the other drugs,the centralized monitoring of large clinical samples shows that unknown or rare adverse drug reactions were very few and the clinical symptoms were mild.