Rationale. Acute respiratory infections (ARIs) are a common problem in the first decade of life. The yearly prevalence of respiratory tract infections in an otherwise healthy 3-year old child is about three to 10 infections. Children between 6 months and 5 years are more prone to develop pharyngitis and tonsillitis compared to older children. 60-70% of children with F/T lies within this age group. Aetiology the pharyngitis and tonsillitis is viral in 70% of all cases In developing countries 6/10 cases are treated using antibiotics, regardless of clinical guidelines or standard of care documents recommending only to use symptomatic drugs (NSAID).~Primary outcome. Duration of symptoms and reduction of pain (odynophagia) severity Secondary outcomes. Days with fever secondary to RTIs; Number of children receiving antibiotic treatment in each treatment group; Days of medical office visits or emergency visits; Total amount of medical office visits or emergency visits during the study, secondary to episodes of RTI; Days of absences from day care centre; Direct and Indirect costs Total costs of treatments including visit to private office, visit to emergency department, cost of treatment (NSAIDs + Probiotics vs NSAIDs + Placebo); Frequency of adverse events; Viral/bacterial load (multiplex-PCR); IgA in saliva and Change in salivary inflammatory biomarkers.~Interventions. L. reuteri DSM 17938 + L. reuteri ATCC PTA 5289) will be given at a dose of 2x10^8 Colony Forming Units (CFU). Five drops are to be taken twice a day (in the morning and in the evening) giving a daily dose of 4x108 CFU/day. The placebo drops will have identical ingredients except for lacking the bacteria. Five drops are to be taken twice a day (in the morning and in the evening).
RCT in children (6m to 5y) with pharyngitis and/or tonsillitis who will be allocated to receive for 10 days L. reuteri DSM 17938 + L. reuteri ATCC PTA 5289) at a dose of 2x10^8 Colony Forming Units (CFU). Five drops are to be taken twice a day (in the morning and in the evening) or placebo drops, as treatment for clinical condition. Duration of symptoms and reduction of pain (odynophagia) severity during treatment will be measured as primary outcome