The goal of this clinical trial is to evaluate the effect of supplementing Bacillus subtilis compared to the control group on the efficacy of Infliximab in patients with Crohn's disease, and to summarize the role of supplementing Bacillus subtilis in the treatment of CD patients.

Participants will be randomized into two groups: the Bacillus subtilis supplementation group and the control group. The patients in the Bacillus subtilis supplementation group received oral Bacillus subtilis capsules for 12 weeks. The control group did not receive additional intervention. Follow up once a week, and after the study, patients will come to the hospital to finish the evaluation indicators.

The goal of this clinical trial is to evaluate the effect of supplementing Bacillus subtilis compared to the control group on the efficacy of Infliximab in patients with Crohn's disease, and to summarize the role of supplementing Bacillus subtilis in the treatment of CD patients.

Participants will be randomized into two groups: the Bacillus subtilis supplementation group and the control group. Patients in the Bacillus subtilis supplementation group take oral Bacillus subtilis capsules once a day, one capsule per time, for 12 weeks, each containing 3×10⁹ CFU of Bacillus subtilis. The control group did not receive additional intervention. Follow up once a week, and after the study, patients will come to the hospital to finish the evaluation indicators.

Inclusion Criteria:

1. Age ≥ 18 years old, ≤ 75 years old;
2. Patients clinically diagnosed with Crohn's disease shall refer to the Chinese Guidelines for the Diagnosis and Treatment of Crohn's Disease (Guangzhou, 2023) for diagnostic criteria;
3. Patients receiving treatment with Infliximab;
4. The patient is currently in the clinical active stage(CDAI≥150 or SES-CD≥3);
5. Agree to participate in this study and sign an informed consent form.

Exclusion Criteria:

Participants who meet any of the following criteria are not eligible for inclusion in this study.

1. Patients with ALT or AST exceeding the normal upper limit by more than twice, and TBIL exceeding the normal upper limit by more than twice;
2. Patients with creatinine clearance rate less than 60ml/min;
3. Patients with severe active infections in the intestines or other areas that require the use of antibiotics or antiviral drugs;
4. Patients with intestinal tuberculosis, other chronic intestinal infectious diseases, and intestinal malignant tumors;
5. Pregnant and lactating women;
6. The fasting blood glucose of patients with diabetes or screening period exceeds 7.0mmol/L or glycosylated hemoglobin exceeds 6.5%;
7. Merge patients with severe mental illness, drug use, alcohol abuse, etc. who are unable to cooperate with the study;
8. Have participated in any other clinical research within the first month prior to enrollment;
9. The researcher determined that any other disease or condition is not suitable for patients participating in this study.

Some data underlying this trial cannot be shared publicly due to protection of participant's privacy.