Gut Microbiota Reconstruction in the Treatment of Irritable Bowel Syndrome With Predominant Diarrhea

Inclusion Criteria: * Age between 18 and 65, no gender limitation; * Had received a diagnosis of IBS-D (as assessed according to the Rome III diagnosis criteria of IBS) and had undergone a colonoscopic examination within the previous 2 years with no organic lesions observed; * Has current symptoms of IBS-D: ①Abdominal pain (at least 2 days in a week with no limitation of severity); ②Stool consistency (rated the consistency of their stools of Bristol types 6/7 at least once a day and at least 2 days in a week); * Can do follow-up at required time points and signed written informed consent before the study. Exclusion Criteria: * Allergic to rifaximin; * Taking alosetron, tegaserod, lubiprostone, warfarin, or antipsychotic, antispasmodic, antidiarrheal, probiotic, or narcotic drugs within the previous 1 month; * Had infective diarrhea history or had taken antibiotics within the previous 14 days; * Patients with a history of inflammatory bowel disease ; * Previous abdominal surgery (other than cholecystectomy or appendectomy); * Human immunodeficiency virus infection or other immunodeficiency conditions such as congenital immunodeficiency or currently taking immune-suppression drugs; * Unstable diabetes, hypertension, thyroid disease, etc; * Accompanied malignant tumor or severe heart/lung/renal/hepatic/brain/blood diseases; * Accompanied severe neural/psychotic diseases such as epilepsy, depression, mania, schizophrenia, etc; * Other conditions that doctor thought not suitable for the study.