Small Intestinal Bacterial Overgrowth

Publication Date: February 1, 2020
Last Updated: March 14, 2022


Diagnosis of SIBO

1. We suggest the use of breath testing (glucose hydrogen or lactulose hydrogen) for the diagnosis of SIBO in patients with IBS. (Conditional (weak)  “We suggest”, Very low)
2. We suggest using glucose hydrogen or lactulose hydrogen breath tests for the diagnosis of SIBO in symptomatic patients with suspected motility disorders. (Conditional (weak)  “We suggest”, Very low)
3. We suggest testing for SIBO using glucose hydrogen or lactulose hydrogen breath tests in symptomatic patients (abdominal pain, gas, bloating, and/or diarrhea) with previous luminal abdominal surgery. (Conditional (weak)  “We suggest”, Very low)

Other conditions associated with SIBO

4. We suggest against the use of breath testing for the diagnosis of SIBO in asymptomatic patients on proton-pump inhibitors (PPIs). (Conditional (weak)  “We suggest”, Very low)
5. We suggest testing for methane using glucose or lactulose breath tests to diagnose the overgrowth of methane-producing organisms (IMO) in symptomatic patients with constipation. (Conditional (weak)  “We suggest”, Very low)
6. We suggest the use of antibiotics in symptomatic patients with SIBO to eradicate overgrowth and resolve symptoms. (Conditional (weak)  “We suggest”, Low)

Recommendation Grading




Small Intestinal Bacterial Overgrowth

Authoring Organization

Publication Month/Year

February 1, 2020

Last Updated Month/Year

August 16, 2023

Supplemental Implementation Tools

Document Type


External Publication Status


Country of Publication


Document Objectives

This guideline statement evaluates criteria for diagnosis, defines the optimal methods for diagnostic testing, and summarizes treatment options for small intestinal bacterial overgrowth

Target Patient Population

Patients with small intestinal bacterial overgrowth

Inclusion Criteria

Female, Male, Adolescent, Adult, Older adult

Health Care Settings

Ambulatory, Hospital, Outpatient

Intended Users

Nurse, nurse practitioner, physician, physician assistant


Assessment and screening, Diagnosis, Management, Treatment

Diseases/Conditions (MeSH)

D001424 - Bacterial Infections, D054328 - Proton Pump Inhibitors, D001419 - Bacteria


proton pump inhibitor, culture, bacterial overgrowth, intestinal bacteria

Source Citation

Pimentel, Mark MD, FRCP(C), FACG; Saad, Richard J. MD, FACG; Long, Millie D. MD, MPH, FACG (GRADE Methodologist); Rao, Satish S. C. MD, PhD, FRCP, FACG. ACG Clinical Guideline, The American Journal of Gastroenterology: February 2020 - Volume 115 - Issue 2 - p 165-178 doi: 10.14309/ajg.0000000000000501