Abstract： AIM To evaluate the effect of adjuvant therapy with Bifidoba-cterium quadruple bacteria tablets on lipid peroxidation injury markers, inflammatory factors, and immune function in patients with ulcerative colitis. METHODS One hundred and ten patients with ulcerative colitis treated from October 2016 to November 2017 at People's Hospital in Longyou County were randomly divided into a control group (n = 55) and an observation group (n = 55). Both groups were given mesalazine, and the observation group was additionally given Bifidobacterium quadruple bacteria tablets. After treatment for 2 mo, the total effective rate, lipid peroxidation injury indexes, inflammatory factors, peripheral T cell subsets, and adverse drug reactions were compared in the two groups. RESULTS After treatment for 2 mo, the total effective rate of the observation group (96.4％) was significantly higher than that of the control group (85.5％; P ＜ 0.05). The levels of ox-LDL, LPO, MDA, IL-6, IL-8, TNF-α、hs-CRP, and CD8+T cells were significantly lower than those before treatment (P ＜ 0.05), and these indexes in the observation group were significantly lower than those of the control group (P＜ 0.05). The levels of SOD, CD4+T cells, and CD4+/CD8+ratio were significantly higher than those before treatment (P ＜ 0.05), and these indexes in the observation group were significantly higher than those of the control group (P ＜0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P ＞; 0.05). CONCLUSION Adjuvant therapy with Bifidobacterium quadruple bacteria tablets in ulcerative colitis patients is significantly effective, which can effectively improve the levels of lipid peroxidation and inflammatory factors and regulate peripheral T cell subsets.