Placebo Controlled Study of 3 Doses of Rifaximin-EIR Tablet to Treat Moderate, Active Crohn's Disease

Inclusion Criteria: * diagnosis of Crohn's disease localised in the ileum and/or colon, documented either radiologically or endoscopically at least 3 months previously; * patients with a CDAI of ≥ 220 to ≤ 400; * patients capable of and willing to conform to the study protocol; * patients who have provided signed and dated written informed consent. Exclusion Criteria: * patients potentially needing immediate surgery for Crohn's disease, including patients with occlusive symptoms and/or stenotic tract with dilation above; * patients with active perianal Crohn's disease; * patients with other infectious, ischemic, or immunological diseases with gastrointestinal involvement; * patients with symptoms attributed to Short Bowel Syndrome or previous surgery; * patients with stoma; * patients affected by upper gastro-intestinal disease (gastro-duodenum-jejunum Crohn's disease) alone or in combination with colitis or ileitis; * patients treated with: oral steroids and budesonide less than 30 days prior to screening; i.v. steroids less than 30 days prior to screening; antibiotics (such as metronidazole, tinidazole, ciprofloxacin, clarithromycin) less than 15 days prior to screening; * rectal steroids less than 30 days prior to the screening visit; * anti-tumour necrosis factor (anti-TNF) and other biological therapies less than 6 months prior to the screening visit; * pregnant women or nursing mothers; * females of childbearing age (unless surgically sterile) without a negative urine pregnancy test at screening and at enrolment; * patients with severe hepatic insufficiency (Child C); * patients with severe cardiac insufficiency (NYHA - New York Heart Association classes 3 - 4); * patients with known hypersensitivity to Rifaximin; * any condition or circumstance that would prevent completion of the study or interfere with analysis of study results, including a history of drug or alcohol abuse, mental illness or non-compliance with treatments or visits, with immunological (including HIV infection), haematological or neoplastic disease; * withdrawal of informed consent; * patients who have used any investigational drug (except biological therapies) within 3 months prior to screening; * patients who have donated 250 ml or more of blood in the last 3 months.