Objective To explore the effect of quadruple regimen combined with vitamin C on blood glucose level in patients with type 2 diabetes mellitus complicated with gastric ulcer.Methods Clinical data of 108 patients with dia-betes mellitus complicated with gastric ulcer admitted to Quanzhou Guangqian Hospital from June 2023 to March 2024 were retrospectively selected and divided into two groups according to different treatment methods,with 54 cases in each group.Both groups were treated with insulin,the control group was treated with quadruple regimen,and the study group was treated with quadruple regimen combined with vitamin C.Blood glucose levels,adverse reactions,and gastric function were compared between the two groups.Results After treatment,fasting blood glucose and 2-hour postprandial blood glucose in the study group were lower than those in the control group,and the differences were sta-tistically significant(both P<0.05).There was no significant difference in the incidence of adverse reactions between the two groups(P>0.05).After treatment,gastrin-17,pepsinogen 1 and pepsinogen 2 in the study group were lower than those in the control group,and the differences were statistically significant(all P<0.05).Conclusion Quadruple regimen combined with vitamin C in the treatment of patients with type 2 diabetes mellitus complicated with gastric ul-cer can reduce the blood glucose level,and the risk of adverse reactions is low,which is helpful to improve the gastric function of patients.