Objective:To study the effects and the mechanism of Faecalibacterium prausnitzii(F.prausnitzii)combined with Kuikeling on colitis of rats with inflammatory bowel disease(IBD). Methods:A total of 50 rats was randomly divided into 5 groups,which named the normal group,the model group,the Kuikeling group,the F.prausnitzii group and the F.prausnitzii combined Kuikeling group,respectively. Each group was given medicine by gavage for a week before model establishment (the normal and model group received saline,the other groups received corresponding F.prausnitzii and Kuikeling). Colitis model was established by 2,4,6-trinitrobenzene sulfonic acid (TNBS) method(80 mg/kg TNBS combined with equad volume ethanol). All rat were killed after 3 days,and mucosal lesion area and colon mucosal inflammation were assessed by the colorectal histological damage scores (HDS). Levels of interleukin-10 (IL-10),interleukin-12 (IL-12),tumor necrosis factor-a (TNF-α)and interferon-γ were detected by ELISA in the plasma,and then we calculated the ratio of IL-10/IL-12. The expressions of IL-10 and TNF-α in the colon mucosal tissues were detected by immunohistochemical(IHC) method. Results:Compared with the model group,mucosal lesion area and the colon HDS were significantly decreased (P < 0.05),the levels of IL-12 and IFN-γ in the plasma(P < 0.05,P < 0.001)and the expression of TNF-α in the colon mucosal tissues (P < 0.05) were significantly decreased in F.prausnitzii combined Kuikeling group,and the level of TNF-α in the plasma was decreased without statistical significance,the levels of IL-10 in the plasma and the colon mucosal tissues(P < 0.05,P < 0.01)and the ratio of IL-10/IL-12(P < 0.05)were significantly increased in the F.prausnitzii combined Kuikeling group. Compared with the Kuikeling group and the F.prausnitzii group,mucosal lesion area and the colon HDS were decreased,the levels of IL-12,IFN-γ,and TNF-α in the plasma and the expression of TNF-α in the colon mucosal tissues were decreased,the levels of IL-10 in the plasma and the colon mucosal tissues,the ratio of IL-10/IL-12 were increased in the F.prausnitzii combined Kuikeling group,but those differences had no statistical significance. Conclusion:The preventive and therapeutic effects ofF.prausnitzii combined Kuikeling is better than single treatment. The immune regulation mechanism may be related to promoting secretion of IL-10 in the plasma and the colon mucosal tissues and decreasing IL-12,TNF-α,IFN-γ levels in the plasma and TNF-α level in the colon mucosal tissues.