Inflammatory Bowel Disease (IBD) are chronic diseases of the gut comprising Crohn's Disease (CD) and Ulcerative Colitis (UC). The symptoms of IBD consist of diarrhea, abdominal discomfort, weight loss, fatigue and rectal bleeding. However, symptoms and treatment vary between patients. Early management of IBD can lead to better response rates and decrease the risk of irreversible bowel damage and future disease complications such as surgeries. Current clinical tools for diagnosis and or assessing progression of IBD are either invasive (colonoscopy), have low patient acceptance (fecal calprotectin) or low accuracy (C-reactive protein). The purpose of this study is to collect clinical data and samples (including blood, breath and stool) donated by patients with IBD and patients with no IBD (controls) to facilitate research that may result in the development of new non-invasive methods of diagnosing IBD and understand the progression of the disease over time in order to better manage IBD patients.

Inclusion Criteria:

• Diagnosed as having Crohn's Disease or Ulcerative Colitis
• Aged 18-70 years.
• Understands the language and signs an informed consent form.
• Any disease location, except isolated upper GI Crohn's disease only
• Any CD or UC disease activity.
• Outpatients and inpatients
• Patients will be recruited, and samples obtained at least one day, and no more than one week, prior to out/inpatient colonoscopy preparation to allow objective assessment of disease activity.

Exclusion Criteria:

• Status post colectomy
• Status post diverting loop ileostomy or end ileostomy or colostomy
• On antibiotics in the past 3 months or currently
• Women (pregnant or breast feeding)
• Subjects with concurrent chronic liver, renal, lung or metabolic disorders
• Active malignancy
• Bowel preparation at day of sample procurement
• Isolated upper GI Crohn's disease only
• Active disease on colonoscopy, but normal fecal calprotectin at inclusion
• C diff. positive at time of inclusion (test to be obtained in routine clinical care).

This is a prospective, controlled, non-interventional cohort study, conducted at the Cleveland Clinic IBD Center, using serially obtained breath and serum headspace VOCs as non-invasive biomarkers to detect disease activity in IBD, fecal calprotectin, CRP, and patient-reported outcome tools. No drug will be evaluated in this study. All visits for this study as well as the initial endoscopy will be based on standard clinical practice and guidelines.

At inclusion, all patients will have a colonoscopy (indication is standard of care), CRP, fecal calprotectin, and baseline PRO2 to establish the pattern for disease activity, which will subsequently be evaluated for change by using fecal calprotectin, CRP, and PRO2 over one year (every 3 months), as a surrogate marker for disease activity.