In this systematic review and meta-analysis, studies on the association of SIBO and PD were searched in PubMed, EMBASE and the Cochrane Library from inception to February 2021. The search terms were as follows: (Parkinson OR Parkinson's disease OR Parkinson's syndrome) AND (small intestinal bacterial overgrowth OR small intestine bacterial overgrowth OR SIBO OR small bowel bacterial overgrowth OR SBBO OR breath test OR lactulose hydrogen OR glucose hydrogen OR jejunal aspirate). References in the articles were assessed to retrieve additional potentially relevant studies. There were no language restrictions.