This randomized, double-blind, placebo-controlled, study aimed to evaluate the effectiveness and safety of a preparation containing echinacea, propolis, and vitamin c in the prevention of respiratory tract infections in children during winter.

Four hundred and thirty children aged 1 to 5 years were randomly assigned to receive either the echinacea preparation or to receive a placebo.

Results demonstrated a preventive effect of the preparation containing echinacea, propolis, and vitamin C on the incidence of respiratory tract infections.

Reference:

Cohen, H.A., Varsano, I., Kahan, E.,  Sarrell, M. E., & Uziel, Y. (2004). Effectiveness of a herbal preparation containing echinacea, propolis, and vitamin c in preventing respiratory tract infections in children: A randomized, double-blind, placebo-controlled, multicenter study. (2004). Archives of Pediatrics & Adolescent Medicine, 158, 217-221. Doi:10.1001/archpedi.158.3.217