Table 1.

Characteristics of included studies in the review.

Study (year)	Methods	Target population	Intervention (probiotic strain)	Outcomes	Notes
Giovannini et al. (2007) [8]	Randomized placebo-controlled, double-blind trial	187 children aged 2–5 yrs	Lactobacillus 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 rhinitis	Exclusion 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 trial	36 subjects aged 14–36 yrs	Lactobacillus rhamnosus. 4 capsules/day for 5.5 months	Changes 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 trial	120 subjects aged 39.3 ± 8.0 years (probiotic) and 39.5 ± 10 (placebo)	Lactobacilluscasei shirota. 80 mL/day for 8 weeks	Change 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 trial	90 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 days	Change in modified pediatric rhinoconjunctivitis quality of life score	Exclusion criteria—steroid treatment, neuropsychiatric disease or congenital immunodeficiency, probiotic allergy
Wang et al. (2004) [12]	Randomized placebo controlled double blind trial	80 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 score	Exclusion criteria—pregnancy, steroid treatment, smoking, neuropsychiatric disease or congenital immunodeficiency or cow's milk allergy
Wheeler et al. (1997) [13]	Randomized crossover design	15 adult patients aged 13 to 45 years	Lactobacillus  acidophilus, Lactobacillus Bulgaricus, and Streptococcus thermophilus. 450 g/day for 2 months	Immune and clinical parameters including pulmonary function tests and quality of life assessments	Exclusion criteria—smoking history, on antibiotics, receiving immunotherapy
Xiao et al. (2006a) [14]	Randomized placebo controlled, double blind trial	40 adult subjects aged 23–61 yrs (probiotic) and 24–55 yrs (placebo)	Bifidobacterium longum536 (BB536). 200 g/day for 14 weeks	Effect on subjective symptoms score	Exclusion criteria—subjects with extreme severe symptom of JCPsis
Xiao et al. (2006b) [15]	Randomized placebo controlled, double blind trial	44 adult subjects aged 22 to 48 yrs (placebo) and 26 to 57 yrs (probiotic)	BB536 powder twice daily for 13 weeks	Effect on subjective symptom scores	Exclusion criteria—subjects with extreme severe symptom of JCPsis
Xiao et al. (2007) [16]	Randomized crossover design	24 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 trial	49 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 weeks	Change in SMS (both nasal and ocular) values	No exclusion criteria stated
Chen et al. (2010) [18]	Randomized placebo controlled, double blind trial	109 children aged 6–12 years	Lactobacillus  salivarius 4 × 109 colony forming units/g/day as a powder mixed with food or water for 12 weeks	The scoring allergic rhinitis index (specific symptoms scores and SMS and blood parameters	Those treated with immunotherapy and those with recurrent respiratory tract and infectious diseases were excluded
Lin et al. (2013) [19]	Randomized placebo controlled, double blind trial	105 children aged 6–12 years	Lactobacillus gasseri A5 capsule (2 × 109 cells/capsule) twice a day for 2 months	Peak expiratory flow rates, symptoms of asthma, and AR scores of the patients, immunological parameters	Those treated with immunotherapy, corticosteroids, and inhaled b2-agonists, anatomical abnormality of the upper respiratory tract and congenital cardiovascular diseases were excluded