Abstract
<title>Abstract</title> <p> <bold>Background:</bold> <italic>Lactiplantibacillus (L.) plantarum</italic> 299v DSM 9843 is a probiotic strain that showed safety and properties potentially beneficial in managing irritable bowel syndrome (IBS). <bold>Objective:</bold> To systematically review and meta-analyze the effects of <italic>L. plantarum</italic> 299v in participants of randomized controlled trials (RCTs) with IBS. <bold>Materials and Methods:</bold> We searched PubMed/MEDLINE, Embase, Scopus, and the Cochrane Central Register of Controlled Trials. A meta-analysis was performed using a random-effects model, pooling the outcomes of abdominal pain, bloating/flatulence, constipation, global symptoms. The trial was registered in PROSPERO (registration number CRD420261322875). <bold>Results:</bold> Six RCTs enrolling 527 adult patients with IBS were included. <italic>L. plantarum</italic> 299v significantly reduced abdominal pain scores (SMD = −2.16; 95% CI: −3.59 to −0.72; <italic>p</italic> = 0.003), abdominal pain severity (SMD = −0.39; 95% CI: −0.67 to −0.12; <italic>p</italic> = 0.005), daily abdominal pain frequency (SMD = −0.66; 95% CI: −1.02 to −0.30; <italic>p</italic> = 0.0004) compared with placebo. The improvement rates of abdominal pain (RR = 4.83; 95% CI: 1.94–11.99; <italic>p</italic> = 0.0007), bloating/flatulence (RR = 1.96; 95% CI: 1.06–3.61; <italic>p</italic> = 0.03) and global symptoms (RR = 4.69; 95% CI, 1.46–15.14; <italic>p</italic> = 0.010) were significantly higher in the probiotic group. No significant effect was observed for constipation (RR= 1.39; 95% CI, 0.32–6.11; <italic>p</italic> = 0.66). <bold>Conclusion:</bold> Meta-analytic evidence supports the capacity of <italic>L. plantarum</italic> 299v to relieve abdominal pain, bloating, flatulence, and general symptoms. The observed diet-dependent response underscores the need for future research to investigate combined probiotic dietary interventions. </p>