Objective To explore the effect of bencycloquidium bromide combined with levocetirizine in the treatment of moderate to severe allergic rhinitis (AR) and its impact on inflammatory factors.Methods A total of 100 patients with persistent moderate to severe AR were selected and randomly divided into monotherapy group (n=50) and combination group (n=50). The monotherapy group was given levocetirizine orally, while the combination group was treated with bencycloquidium bromide nasal inhalant on the basis of oral levocetirizine. Both groups were treated for 4 weeks. Visual analog scale (VAS) scores between the two groups before treatment and at 2 and 4 weeks of treatment were compared, and venous blood was collected to detect serum inflammatory factor [interleukin(IL)-1β, IL-4, IL-6] levels before treatment and 4 weeks of treatment, and adverse reactions were recorded.Results Before treatment, there were no statistically significant differences in VAS scores and serum inflammatory factor levels between the monotherapy group and the combination group (P>0.05). Compared with before treatment, the VAS scores and serum inflammatory factor levels in both groups decreased after treatment. After 2 weeks of treatment, the VAS score, sneezing, itching, and rhinirrhea scores of the combination group were lower than those of the monotherapy group, and the differences were statistically significant (P<0.05). After 4 weeks of treatment, the VAS score, sneezing, itching, rhinirrhea, congestion scores, and serum inflammatory factor (IL-1β, IL-4, IL-6) levels in the combination group were lower than those in the monotherapy group, and the differences were statistically significant (P<0.05). No serious adverse reactions occurred in both groups during treatment.Conclusion The combination of bencycloquidium bromide and levocetirizine is more effective in treating moderate to severe AR than levocetirizine alone, without increasing adverse reactions.