EMM Quigley, JA Murray, M Pimental. Gastroenterol 2020; 159: 1526-1532. Clinical Practice Guidelines. Full Free Text: AGA Clinical Practice Update on Small Intestinal Bacterial Overgrowth: Expert Review
This is a really lousy clinical practice guideline but a pretty good review of small intestinal bacterial overgrowth (SIBO). The reason why it is lousy: it provides virtually no recommendations on how to define/diagnose SIBO, does not recommend specific testing and equivocates on specific treatments.
Here are a few of the “best practice advice” as examples:
- #1 The definition of SIBO as a clinical entity lacks precision and consistency; it is a term generally applied to a clinical disorder where symptoms, clinical signs, and/or laboratory abnormalities are attributed to changes in the numbers of bacteria or in the composition of the bacterial population in the small intestine
- #5 A major impediment to our ability to accurately define SIBO is our limited understanding of normal small intestinal microbial populations
- #6 Controversy remains concerning the role of SIBO in the pathogenesis of common functional symptoms, such as those regarded as components of irritable bowel syndrome
- #9 There is a limited database to guide the clinician in developing antibiotic strategies for SIBO
While not providing ‘best practical advice,’ the article does provide details regarding limitations in testing, underlying pathogenesis, and potential treatment regimens for adults.

Related blog posts:
- ACG Guideline for Small Intestinal Bacterial Overgrowth | gutsandgrowth 2020. One key point is that the authors acknowledge that almost all of their recommendations are based on a very low level of evidence.
- Breath Test Reliability for Bacterial Overgrowth 2016
- Breath Test Reliability for Bacterial Overgrowth 2015