Table 1.

Results of clinical trials with probiotics in irritable bowel syndrome

Ref.	Patients (n)	Duration of therapy	Probiotic strains	Dose (CFU/d)	Outcomes
Maupas et al[88]	34	1 mo	Saccharomyces boulardii	9 × 109	Improved stool number and consistency
Gade et al[89]	54	1 mo	Paraghurt (Streptococcus faecium)	1 × 10¹²	Improved symptoms
Halpern et al[90]	18	4 mo	Lactobacillus acidophilus	2 × 1010	Improved symptoms
O’Sullivan et al[91]	25	1 mo	Lactobacillus GG	1 × 1010	No benefit
Nobaek et al[92]	60	1 mo	Lactobacillus plantarum 299V Pro-Viva®	5 × 107	Improved global symptoms
Niedzielin et al[93]	40	1 mo	Lactobacillus plantarum 299V Pro-Viva®	2 × 1010	Improved global symptoms
Kim et al[94]	25	2 d-IBS	VSL3®	9 × 10¹¹	Reduced bloating
Tsuchiya et al[95]	68	3 mo	Lactobacillus acidophilus	1.5 × 106	Improved symptoms
			Lactobacillus helveticus	1.3 × 109
			Bifidobacterium	4.95 × 109
O’Mahony et al[96]	80	2 mo	Bifidobacterium longum subspecies infantis vs Lactobacillus salivarius	1 × 1010	B. infantis: improved global symptoms and anti-inflammatory cytokine profileLactobacillus salivarius: no benefit
Kajander et al[97]	103	6 mo	Mixture (2 strains of Lactobacillus rhamnosus, Bifidobacterium breve, Propionibacterium freudenreichii)	8-9 × 109	Improved global symptoms
Bittner et al[98]	25	0.5 mo	29 bacteria + prebiotic Prescript-Assist®	2.6 × 108	Improved wellbeing
Sen et al[99]	12	1 mo	Lactobacillus plantarum 299V Pro-Viva®	5 × 107	No benefit; Study design flawed
Bausserman et al[100]	50	1.5 mo	Lactobacillus GG	2 × 1010	No benefit
Niv et al[101]	39	6 mo	Lactobacillus GG	2 × 108	No benefit Francis severity IBS score
Kim et al[102]	48	1 or 2 mo	VSL3®	8 × 109	Reduced flatulence, retarded colonic transit
Whorwell et al[103]	362	1 mo	Bifidobacterium longum subspecies infantis 35 624 in 3 doses	1 × 106	Improved global symptoms
				1 × 108
				1 × 1010
Long et al[104]	60	0.5 mo	Bifidobacterium	2 × 108	Symptoms resolved
Gawrońska et al[105]	104	1 mo	Lactobacillus GG	6 × 109	Reduced frequency of pain
Moon et al[106]	34	1 mo	Bifidobacterium subtilis, Streptococcus faecium	750 mL/d, CFU/d not given	Reduced frequency pain
Marteau et al[107]	116	1 mo	Lactibiane® (4 strains of Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus lactis, Streptococcus thermophilus)	1 × 1010	Reduced painIncreased colonic transit in those with constipation
Simrén et al[108]	76	1.5 mo	Lactobacillus plantarum 299V	2 × 109	No benefit
Simrén et al[109]	118	2 mo	Lactobacillus paracasei ssp paracasei	2 × 1010	No benefit
Guyonnet et al[110]	274	1.5 mo	Bifidobacterium animalis, Streptococcus thermophilus and Lactobacillus bulgaricus	1.25 × 1010 1.2 × 109	Improved bloating and constipation
Drouault-Holowacz et al[111]	116	1 mo	Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus lactis, Streptococcus thermophilus	1 × 1010	Not significant in relieving symptoms
Sinn et al[112]	40	1 mo	Lactobacillus acidophilus	2 × 108	Improved abdominal pain and discomfort
Enck et al[113]	297	1 mo	Escherichia coli, Enterococcus faecalis	4.5 × 102	Improvement in pain
Hun et al[114]	44	2 mo	Bacillus coagulans	8 × 108	Improvement abdominal pain and bloating
Dolin et al[115]	61	2 mo	Bacillus coagulans	2 × 109	Diminution of diarrhea
Ligaarden et al[116]	16	1 mo	Lactobacillus plantarum	1010/L	Worsening of symptoms
Moayyedi et al[117]	19 randomised controlled trials in 1650 patients				Probiotics appear to be efficacious but the magnitude of benefit and the most effective strains are uncertain