Participants will be given FMT through oral capsules or nasojejunal tube once a month. After three-time treatment, participants were followed up for three months. Participants complete specific scales to assess improvement in symptoms, emotion and quality of life. Besides, they report adverse effects and collect fecal samples at each visit.
Patients who fulfilled the Rome IV criteria for the diagnosis of IBS, aged 18-70 years;
Patients who have experienced failure of at least 3 conventional therapies for IBS;
Absence of red flags such as weight loss, hematochezia;
Pregnant, planning pregnancy or lactating;
Psychiatric disorder or unable to cooperate with treatment and follow-up visit;
Immunodeficiency or treatment with immune-modulating medication;
Use of probiotics within the previous 3 months or treatment with antibiotics within 1 month prior to study entry;