Nancy Toedter Williams


Am J Health Syst Pharm. 2010;67(6):449-458. 

In This Article


IBS is characterized by abdominal pain, bloating, flatulence, and altered bowel habits. These symptoms may be due to bacterial overgrowth in the small intestine, causing increased fermentation activities and gas production.[37] Some studies suggest that probiotics may be beneficial in reducing bloating and flatulence associated with IBS. The probiotics used most frequently in the treatment of IBS include lactobacilli and bifidobacteria. In addition, a combination product (VSL#3, VSL Pharmaceuticals, Inc., Towson, MD) has reduced abdominal bloating and flatulence. This preparation contains eight bacterial organisms in large numbers: three bifidobacteria (Bifidobacterium longum, Bifidobacterium infantis, and Bifidobacterium breve), four lactobacilli (L. acidophilus, Lactobacillus casei, L. bulgaricus, and L. plantarum), and S. thermophilus.[12,24]

A recent meta-analysis involving 20 trials (n = 1404) found that probiotics (most commonly lactobacilli and bifidobacteria) improved global IBS symptoms (RRpooled, 0.77; 95% CI, 0.62–0.94) and reduced abdominal pain (RRpooled, 0.78; 95% CI, 0.69–0.88) compared with placebo.[38] This meta-analysis was not able to examine other types of individual IBS symptoms (e.g., bloating or distension, flatulence, stool frequency) or the effectiveness of specific probiotic strains due to insufficient data. A review of 14 clinical trials also revealed that probiotics (most commonly lactobacilli, bifidobacteria, and VSL#3) improved overall symptoms associated with IBS compared with placebo; however, the contributing studies had methodological limitations.[37] Although probiotics may be beneficial in treating IBS symptoms, limitations exist in interpreting trial results due to the lack of standardization of strains, dosages, treatment durations, and assessment of clinical outcomes. More data are needed before probiotics can be recommended as typical care in the treatment of IBS.[37,38]


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