The purpose of this study is to evaluate the efficacy as well as safety of rifaximin combined fecal microbiota transplantation(Gut microbiota reconstruction) in the treatment of IBS-D.

In this prospective study, there is only one group with no placebo/blank control. All qualified IBS-D patients could be admitted to hospital for at least one time of combing therapy (taking rifaximin for 3 days and then receiving fecal microbiota transplantation) and follow-up until 6 months after the first treatment.

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.