To observe the therapeutic effect of Yuye Decoction on type 2 diabetes mellitus complicated with carotid atherosclerosis and its effect on peripheral blood T lymphocytes and related cytokines.Methods:A total of 98 patients with type 2 diabetes mellitus complicated with carotid atherosclerosis admitted to Dezhou Hospital of Traditional Chinese Medicine from April 2017 to April 2019 were selected as the research objects and were randomly divided into a control group (n=49) and an observation group (n=49).The control group was treated with routine Western medicine for lowering blood sugar and lipid,while the observation group was treated with Yuye Decoction on the basis of the control group for 8 weeks.The changes of blood glucose,oxidative stress,T lymphocytes and their cytokines and inflammatory factors were observed in each group.Results:1) At the end of the course of treatment,the levels of helper T cells (Th1),Th17,interleukin-2 (IL-2),IL-17,γIFN,malondialdehyde (MDA) and 8-isoprostaglandin F2a (8-ios-PGF2a) in the 2 groups were significantly lower than those before treatment.However,Th2,(Treg),IL-4,IL-6,1L-10 of regulatory T cells and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) of regulatory T cells were significantly higher than those before treatment,and the above indexes in the observation group were significantly higher than those in the control group (P<0.05).2) At the end of treatment,homocysteine (Hcy),procalcitonin (PCT),hypersensitive C-reactive protein (hs-CRP) and tumor necrosis factor-α (TNF-α) in both groups were significantly lowered (P<0.05),and those in the study group were significantly lower than those in the control group (P<0.05).3) At the end of the course of treatment,fasting blood glucose (FBG),2-hour postprandial blood glucose (2 hPBG),glycosylated hemoglobin (HbA1c) and carotid intima-media thickness (IMT) in the 2 groups were significantly lower than those before treatment,and those in the observation group were significantly lower than those in the control group (P<0.05).4)The markedly effective rate and total effective rate of the observation group were 53.06% and 89.79% respectively,which were significantly higher than 34.69% and 75.51% of the control group (P<0.05).Conclusion:Yuye Decoction can effectively reduce the Degree of carotid artery stenosis in patients with type 2 diabetes mellitus complicated with carotid atherosclerosis,and its mechanism may be related to anti-inflammatory and antioxidant stress.