Balloon-assisted Enteroscopy and Bacteria

Inclusion Criteria: * adult patients with clinical suspicions of small intestinal lesions in need of balloon-assisted enteroscopy examinations * signed written informed consents Exclusion Criteria: * Patients with active infection or receiving systemic (oral or intravenous) antibiotics within recent 3 months (this may decrease effect of bacterial translocation) or taking drugs that may affect renal function within 3 months * Unstable health condition for balloon-assisted enteroscopy (unstable hemodynamics, severe cardiopulmonary compromise) * Pregnancy * known allergy to lactulose, mannitol * Refuse to sign written informed consent of this study. * patients would be advised to hold prokinetic agents