Some studies have shown that rifaximin is effective in the management of Crohn's Disease. Meanwhile, its adverse effect is tolerable. But no study has been conducted to assess its effect on preventing postoperative recurrence. Thus, we conduct a randomised controlled study to assess the effect of rifaximin combined with thiopurine on preventing postoperative endoscopic recurrence in Crohn's disease, compared with thiopurine. The primary endpoint is the rate of endoscopic recurrence at 6 months.

Inclusion Criteria:

1. Consecutive patients with Crohn's disease undergoing intestinal resection of all macroscopic diseased bowel, with an endoscopically accessible ileocolic anastomosis;
2. Enrolled patients must have one or more risk factor for the development of postoperative recurrence including penetrating disease behaviour, prior bowel resection, and active smoking.

Exclusion Criteria:

1. Severe comorbidities;
2. With a stoma;
3. With malignancy;
4. Pregnancy;
5. Intolerant of thiopurine drugs;
6. With contraindication of using rifaximin or thiopurine drugs.