Objective To investigate the relationship between regulatory T(Treg)cells and recurrence after treatment with mometasone furoate in children with adenoid hypertrophy complicated with allergic rhinitis.Methods A total of 104 children with adenoid hyperplasia complicated with allergic rhinitis admitted to Chan-gzhou Maternal and Child Health Care Hospital from January 2021 to January 2023 were selected as the study subjects.All the children were treated with mometasone furoate for 1 month.According to whether the drug relapsed after 3 months,the patients were divided into recurrence group and the non-recurrence group.The pe-ripheral blood Treg cells,intracellular cytokine interleukin-10(IL-10),transforming growth factor β1(TGF-β1),IgE,IgG4 levels,and eosinophilic count(EOS)were measured in both groups before and after treatment.The adenoid/nasopharynx(A/N)value and symptom scores of allergic rhinitis were measured 3 months after drug withdrawal in the two groups.Pearson analysis was used to evaluate the correlation between Treg cells and A/N value and symptom scores.The effectiveness of Treg cells,IL-10,TGF-β1,IgE,IgG4,and EOS in predicting the recurrence was evaluated by receiver operating characteristic(ROC)curve.Results The recur-rence rate of 104 children with adenoid hypertrophy complicated with allergic rhinitis was 41.35％(43/104).After treatment,Treg cells,IL-10,TGF-β1 and IgG4 in the recurrent group were lower than those in the non-recurrent group,while IgE,EOS,A/N value and symptom score were higher than those in the non-recurrent group,with statistical significance(P＜0.05).Pearson analysis showed that Treg cells were negatively corre-lated with A/N value(r=-0.470,P＜0.001)and rhinitis symptom scores(r=-0.872,P＜0.001).The accuracy,sensitivity and specificity of Treg cells in predicting the prognosis were 94.6％,95.1％and 93.0％respectively.Conclusion Treg cells are effective in predicting the prognosis of children with adenoid hypertro-phy complicated with allergic rhinitis.