ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth

Am J Gastroenterol. 2020 Feb;115(2):165-178. doi: 10.14309/ajg.0000000000000501.


Small intestinal bacterial overgrowth is defined as the presence of excessive numbers of bacteria in the small bowel, causing gastrointestinal symptoms. This guideline statement evaluates criteria for diagnosis, defines the optimal methods for diagnostic testing, and summarizes treatment options for small intestinal bacterial overgrowth. This guideline provides an evidence-based evaluation of the literature through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process. In instances where the available evidence was not appropriate for a formal GRADE recommendation, key concepts were developed using expert consensus.

Publication types

  • Practice Guideline

MeSH terms

  • Anti-Bacterial Agents / therapeutic use*
  • Blind Loop Syndrome / diagnosis*
  • Blind Loop Syndrome / therapy*
  • Breath Tests
  • Culture Techniques
  • Diet Therapy*
  • Fecal Microbiota Transplantation*
  • Humans
  • Hydrogen / analysis
  • Intestine, Small
  • Methane / analysis
  • Probiotics / therapeutic use*
  • Suction


  • Anti-Bacterial Agents
  • Hydrogen
  • Methane