Objective To analyze the prophylactic effect and the cost-effectiveness of Carmine Leaf Granules on the colds of chlildren in "families of two children" and evaluate its clinical promotional value in preventing the colds in children. Methods From October 2020 to March 2021, 112 cases of children with cold in the emergency department of the Children′s Hospital of Jiangxi Province, another child with a possible history of cold exposure was selected as the research object. The subjects were randomly divided into study group and control group by drawing lots, with 56 cases in each group. In the study group, Carmine Leaf Granules were taken orally, and Oseltamivir Granules were also taken orally if the children in the family were suffering from influenza. The control group did not do intervention. If the children in this family were treated with influenza, Oseltamivir Granules were taken orally. All the children were treated with Carmine Leaf Granules oral plus symptomatic treatment. The incidence of colds, total cost, per capita cost and percentage of people without colds within 1 week were compared between the two groups, and a cost-benefit analysis was conducted. Results In 112 cases, the remission rate of cold was 81.25%. There were no significant differences in age, gender and malnutrition between the study group and the control group (P>0.05). The incidence of cold in the study group was lower than that in the control group, and the difference was statistically significant (P<0.05). The costbenefit ratio of the study group was lower than that of the control group. Conclusion Carmine Leaf Granules has good preventive value and cost-effectiveness on the colds of chlildren.