Objective. To evaluate the effectiveness of the natural terpenoids complex in preschool children with recurrent acute respiratory infections (ARI).Material and methods. There were examined 7129 children of 3-7 years old, they were divided into 3 groups. In main group (n = 2400) there was endonasally (on the mucous membrane of the nasal cavity with cotton buds) used a complex of natural terpenoids 2 times a day (morning and evening) 5 days a week for 1 - 3 months. Prevention and treatment of children from the comparison group (n = 2,379) was carried out with dioxotetrahydroxy tetrahydronaphthalene. The control group consisted of children (n = 2,350), who received no therapy. Upon completion of the course of therapy, children were examined in dynamics.Results. The authors noted positive clinical effect of the natural terpenoid complex, as evidenced by a 1.6 times decrease in acute respiratory infections during the year and the duration of the acute episode of the disease by 2.5 days, as well as a positive effect on the elimination of Epstein Barr virusin frequently ill children when using drug for 65.51 ± 2.98 days. The authors observed a favorable clinical effect against the decrease in neutrophils and eosinophils in the rhinocytogram, as well as mixed flora and cocci, indicating a decrease in mucosal neutrophilic inflammation and prevention of bacterial complications.