Introduction Xiyanping injection (XYP), a type of Traditional Chinese Medicine, is often applied in combination with other medications in treating bronchitis, tonsillitis, and bacillary dysentery in China, which is evidently associative with allergic reactions. In recent years, XYP’s adverse drug reactions (ADRs), represented by allergic reactions, have emerged throughout the country.Objective This study aims to investigate the association between the concomitant use of XYP and 25 most frequently co-applied medications with suspected allergic reactions for China’s patients receiving XYP.Methods A nested case-control study was conducted using the sampling data from 2015 China’s Urban Employees Basic Medical Insurance and Urban Residents Basic Medical Insurance database. Four anti-allergic marker drugs were used to evaluate suspected allergic reactions. Univariate analyses and multivariable conditional logistic regression were conducted, and results were reported as odds ratios (ORs) with 95% confidence interval (CI). Sensitivity analyses were performed on the expanded sample by including those prescribed with anti-allergic marker drugs on the same day as XYP and then stopped XYP on the next day.Results Out of 57,612 participants with XYP prescription, we got 949 matched case-control pairs. Multivariable conditional logistic regression revealed that seven concomitant medications including gentamicin (OR = 4.3; 95% CI [2.5, 7.3]), cefoperazone-sulbactam (OR = 4.3; 95% CI [1.4, 13.0]), lidocaine (OR = 2.8; 95% CI [1.8, 4.2]), aminophylline (OR = 1.7; 95% CI [1.1, 2.9]), ribavirin (OR = 1.5; 95% CI [1.1, 2.1)), potassium chloride (OR = 1.4; 95% CI [1.1, 1.9]), and vitamin C (OR = 1.3; 95% CI [1.0, 1.7]) were associated with increased risk, while cefathiamidine (OR = 0.3; 95% CI [0.2, 0.5]) was associated with reduced risk. Sensitivity analysis on 2,438 matched pairs revealed similar findings. Conclusion Increased risks for suspected allergic reactions were found for the concomitant use of XYP with seven medications. Our data suggest that gentamicin, cefoperazone-sulbactam, lidocaine and ribavirin should be applied with precautions for patients receiving XYP, and further studies on drug interactions and allergy mechanisms are warranted.