This study aims to assess if adverse drug reactions (ADRs) to Kudiezi injection are allergic in origin. Hospital information system (HIS) data from 18 hospitals in China were used to carry out a nested case control design study. Included were patients who received dexamethasone for suspected allergic reactions after receiving Kudiezi injection. These were compared with non-allergic reaction people. Single factor logistic regression and multiple factor logistic regression were used to analyze data. Condition on admission, allergic history, dosage, disease status and drug combinations were taken into account in cases of suspected allergic reactions. After analysis in two subgroups we found that the condition on solvents had a significant effect, P values were 0.005 5 and < 0.000 1 on suspected cases of allergic reactions. For the first subgroup analysis, we found using other eight injections at the same time as Kudiezi injection could be risk factors in suspected cases of allergic reactions. For the second subgroup analysis combining using mannitol or fructose could increase risks. Based on this current research, condition on admission as well as the concomitant use of some other drugs may be the risk factors in suspected cases of allergic reactions. However, further research for verification is required. This study can provide guidance for safe clinical practice in using Kudiezi injection.