Table 1: Characteristics of included studies in the review.

Study (year)MethodsTarget populationIntervention (probiotic strain)OutcomesNotes

Giovannini et al. (2007) [8]Randomized placebo-controlled, double-blind trial187 children aged 2–5 yrsLactobacillus bulgaricus, Streptococcus thermophilus,
and Lactobacillus casei. 100 mL/day for 12 months
Number of days free from and cumulative number and duration of episodes of asthma and/or rhinitisExclusion criteria—cow’s milk or food allergy, lactose intolerance, chronic disease, perinatal respiratory problems, antibiotic use in the preceding 4 wk before starting intervention

Helin et al. (2002) [9]Randomized placebo controlled double blind trial36 subjects aged 14–36 yrsLactobacillus rhamnosus. 4 capsules/day for 5.5 monthsChanges in allergic nose, eye, lung, and total symptom scores Exclusion criteria—other pollen allergies, smoking, pregnancy and lactation, use of immunotherapy or long-term medication or antibiotics and probiotic products

Tamura et al. (2007) [10]Randomized placebo controlled, double blind trial120 subjects aged 39.3 ± 8.0 years (probiotic) and 39.5 ± 10 (placebo) Lactobacilluscasei shirota. 80 mL/day for 8 weeksChange in symptom medication score (SMS)Exclusion criteria—use of antihistamines or antiallergic medication, upper respiratory tract infection or polyp, asthma, severe chronic systemic disorder, hyposensitization therapy, cow’s milk allergy, drinking dairy products containing lactic acid bacteria

Peng and Hsu (2005) [11]Randomized placebo controlled, double blind trial90 subjects
aged 16.07 ± 2.11 yrs (live probiotic), 14.50 ± 1.78 (heat-killed probiotic), 16.60 ± 2.02 (placebo)
Lactobacillus paracasei. 2 capsules/day for 30 daysChange in modified pediatric rhinoconjunctivitis quality of life scoreExclusion criteria—steroid treatment, neuropsychiatric disease or congenital immunodeficiency, probiotic allergy

Wang et al. (2004) [12]Randomized placebo controlled double blind trial80 children aged 15.87 ± 1.53 yrs (probiotic) and 14.00 ± 1.90 (placebo)Lactobacillus
 paracasei-33. 200–400 mL/day for 30 days
Change in modified pediatric rhinoconjunctivitis quality of life scoreExclusion criteria—pregnancy, steroid treatment, smoking, neuropsychiatric disease or congenital immunodeficiency or cow’s milk allergy

Wheeler et al. (1997) [13]Randomized crossover design15 adult patients aged 13 to 45 yearsLactobacillus
acidophilus,
Lactobacillus Bulgaricus, and
Streptococcus thermophilus. 450 g/day for 2 months
Immune and clinical parameters including pulmonary function tests and quality of life assessmentsExclusion criteria—smoking history, on antibiotics, receiving immunotherapy

Xiao et al. (2006a) [14]Randomized placebo controlled, double blind trial40 adult subjects aged 23–61 yrs (probiotic) and 24–55 yrs (placebo)Bifidobacterium longum536 (BB536). 200 g/day for 14 weeksEffect on subjective symptoms scoreExclusion criteria—subjects with extreme severe symptom of JCPsis

Xiao et al. (2006b) [15]Randomized placebo controlled, double blind trial44 adult subjects aged 22 to 48 yrs (placebo) and 26 to 57 yrs (probiotic)BB536 powder twice daily for 13 weeksEffect on subjective symptom scores Exclusion criteria—subjects with extreme severe symptom of JCPsis

Xiao et al. (2007) [16]Randomized crossover design24 adult subjects aged 41.0 ± 8 yrs (group-A) and 37.6 ± 7 yrs (group-B)BB536 powder
twice a day for 8 weeks
Effect on symptom and medication score No exclusion criteria stated

Ishida et al. (2005) [17]Randomized placebo controlled, double blind trial49 adult subjects aged 34.0 ± 3.4 yrs (intervention)
and 36.9 ± 3.0 yrs (placebo)
Lactobacillus    acidophilus L-92. 100 mL/day for 8 weeksChange in SMS (both nasal and ocular) valuesNo exclusion criteria stated

Chen et al. (2010) [18]Randomized placebo controlled, double blind trial109 children aged 6–12 yearsLactobacillus  salivarius 4 × 109 colony forming units/g/day as a powder mixed with food or water for 12 weeksThe scoring allergic rhinitis index (specific symptoms scores and SMS and blood parametersThose treated with immunotherapy and those with recurrent respiratory tract and infectious diseases were excluded

Lin et al. (2013) [19]Randomized placebo controlled, double blind trial105 children aged 6–12 yearsLactobacillus gasseri A5 capsule (2 × 109 cells/capsule) twice a day for 2 monthsPeak expiratory flow rates, symptoms of asthma, and AR scores of the patients, immunological parametersThose treated with immunotherapy, corticosteroids, and inhaled b2-agonists, anatomical abnormality of the upper respiratory tract and congenital cardiovascular diseases were excluded