BackgroundCurrent recommendations for patients with irritable bowel syndrome to partake in physical activity do not incorporate evidence from all available randomised control trials (RCTs), with little information regarding potential adverse effects.AimTo assess the benefits and harms of physical activity interventions in adults diagnosed with irritable bowel syndrome.MethodTen electronic databases including CENTRAL, MEDLINE and EMBASE were searched until 24 November 2017 for RCTs comparing a physical activity intervention with no intervention, usual care, or another intervention; assessing a validated measure of symptoms, quality of life (QoL), and bowel movement in any setting.ResultsNine RCTs with data for 326 participants were included. Interventions included yoga (n = 5), advice and support (n = 2), treadmill exercise (n = 1), and Qigong (n = 1) compared with usual care (n = 4), walking (n = 2), diet (n = 1), or medication only (n = 2). A meta-analysis of three studies demonstrated a large and statistically significant improvement in reported IBS symptoms (standardised mean difference −1.06, 95% confidence interval = −2.08 to −0.04; N = 84). However, evidence was rated as very low quality, providing very little confidence in the effect estimate. In additional meta-analyses, physical activity did not conclusively demonstrate improvements in QoL or abdominal pain. The quality of evidence was judged very low and low respectively, providing little confidence in the effect estimates. There was insufficient evidence to assess adverse effects due to poor trial reporting.ConclusionA small body of low to very-low quality evidence suggests physical activity may improve symptoms but not QoL or abdominal pain in people with irritable bowel syndrome but findings are uncertain.