Respiratory tract infection is a common disease and occurs in all age, especially in children and the elderly are usually more serious. Usually when there is a bacterial infection, antibiotics are prescribed. However, the use of antibiotics often causes patients gastrointestinal discomfort, diarrhea and drug resistance. In recent years, many of the clinical trial results showed that administration of probiotics can reduce the incidence of respiratory tract infections, symptoms, duration of disease and reduce the use of antibiotics. So that probiotics may provide another way to prevent respiratory tract infection.