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Am Fam Physician. 2020;102(6):377

Clinical Question

Does a fecal microbiota transplant safely improve symptoms in patients with irritable bowel syndrome?

Bottom Line

This is the largest and best study to date of fecal microbiota transplant for irritable bowel syndrome (IBS)—with impressive results. The authors argue that the quality of donor stool is an important factor and may explain the differences in results (one previous study had positive findings, the other did not). Although findings persisted and even improved between one and three months posttransplant, it is unclear how long the benefits will persist. (Level of Evidence = 1b)


When we call something a syndrome, that often means we do not know what causes it or how to treat it. It seems like bacteria in the gut may have something to do with IBS. These authors identified 200 Norwegian patients who met the Rome IV criteria for IBS and who had no red flags for inflammatory bowel disease or malignancy. A 12-week course of dietary manipulation therapy had been ineffective. At baseline, a stool sample was taken. After excluding 35 patients, largely because of withdrawal of consent or declining participation, the authors randomized the remaining 165 patients to one of three groups: placebo (transplant with 30 g of their own stool), 30-g fecal microbiota transplant, or 60-g fecal microbiota transplant. The fecal microbiota transplants were administered via upper endoscopy. The average age of participants was 40 years, 81% were women, and most had constipation- or diarrhea-predominant IBS rather than mixed. The donor was a healthy, nonsmoking male who had received only three courses of antibiotics in his life and ate a healthy diet. A variety of IBS-specific scores were measured, and a response was defined as a reduction in the IBS Severity Scoring System score of at least 50 points at three months' follow-up. This occurred in 24% of the patients who received placebo, 77% who received the 30-g fecal microbiota transplant, and 89% who received the 60-g fecal microbiota transplant. These differences were statistically and clinically significant, with a number needed to treat of 2 for one person to benefit. The benefit was similar for subgroups by type of IBS, sex, and duration of IBS symptoms. Patients reported improvements in quality of life, fatigue, and abdominal symptoms using validated survey instruments. The authors also analyzed the stool specimens after treatment and saw significant differences in some species.

Study design: Randomized controlled trial (double-blinded)

Funding source: Foundation

Allocation: Concealed

Setting: Outpatient (specialty)

Reference: El-Salhy M, Hatlebakk JG, Gilja OH, et al. Efficacy of faecal microbiota transplantation for patients with irritable bowel syndrome in a randomised, double-blind, placebo-controlled study. Gut. 2020;69(5):859–867.

Editor's Note: Dr. Ebell is deputy editor for evidence-based medicine for AFP and cofounder and editor-in-chief of Essential Evidence Plus, published by Wiley-Blackwell.

POEMs (patient-oriented evidence that matters) are provided by Essential Evidence Plus, a point-of-care clinical decision support system published by Wiley-Blackwell. For more information, see Copyright Wiley-Blackwell. Used with permission.

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