Patients with confirmed Crohn's disease undergoing intestinal resection for complicated Crohn's disease - will be followed for one year, and undergo a follow- up colonoscopy between 6-9 months after surgery. Patients will be seen at enrollment and follow-up visits, 3,6,9& 12 months after surgery. At enrollment, sites of disease, age of onset, smoking history and previous medication use will be registered, as well as presence of strictures and fistula, or previous surgery. At all visits, patients will be questioned regarding disease symptoms, smoking, and medication use. During each of the follow-up visits, patients will be examined, weighed, and have a disease activity index recorded. At all follow-up visits, they will undergo the following tests; CBC, ESR, CRP, and fecal calprotectin. Sera will be stored for antibodies such as ASCA or anti glycan antibodies.