The purpose of this study is to investigate if the probiotic Bifidobacterium breve Bif195 (Bif195) will result in improvement in clinical outcome in patients with small intestinal Crohn's disease.

Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) with an incidence rate at 11/100 000 per year in Denmark.

The disease can potentially affect the entire gastrointestinal tract, though the most common affected area is terminal ileum and the adjacent part of colon.

CD is a result of both genetic and environmental factors together with the intestinal microbiota, however the precise etiology is unclear.

A change of the intestinal microbiota with a reduced occurrence of e.g. Bacteroides species, Firmicutes and the anti-inflammatory bacteria Faecalibacterium prausnitzii is found in CD patients compared to healthy controls. Also a reduction of the mucosa-associated Bifidobacteria has been associated with the risk of mucosal inflammation.

The hypothesis that an imbalance between potentially beneficial and pathogenic bacteria contribute to the pathogenesis of IBD, including CD, has led to the suggestion that manipulation of the microbiota may be an attractive target for therapeutic interventions in IBD.

A new probiotic bacterium, Bifidobacterium breve Bif195 (Bif195) has been identified and has shown great effects on preventing enteropathy and ulcers on the gut mucosa in healthy volunteers given acetylsalicylic acid (13), and thereby Bif195 has also shown a potential in reducing gut permeability defects. This bacterium has not yet been investigated in CD patients.

Inclusion Criteria:

• Diagnosed with small intestinal CD
• Fecal calprotectin ≥ 250 ug/g
• IUS evidence of small bowel inflammation with wall thickness ≥ 4 mm
• At least 3 months af stable medical treatment
• Able to read and speak Danish

Exclusion Criteria:

• Positive rectal swab for pathogenic microorganisms
• Use of antibiotics, probiotics and systemic glucocorticosteroids within 4 weeks prior to inclusion
• Participation in other clinical trials within 30 days prior to inclusion
• Pregnancy, planned pregnancy or breast feeding
• Psychiatric disease
• Abuse of alcohol or drugs