An experimental model of colitis is established by giving mice a 2% DSS solution to drink for 7 days. Mice are supplemented exogenously with A. muciniphila, B. fragilis ZY3-312, or PBS as a control treatment 14 days before the model is established and during the DSS modeling process. Then, DSS is replaced with filtered drinking water, and mice are sacrificed on the 3rd or 5th day after the removal of DSS and colon tissue is extracted, and a proteomics study is conducted based on iTraq technology.