Objective To survey the incidence of recurrent aphthou ulcer among high school students of Nanning. Methods A total of 2107 high school students were enrolled as the research subjects using random cluster sampling,then the incidence of recurrent aphthou ulcer were investigated and analyzed.Results The incidence rate of recurrent aphthou ulcer among high school students of Nanning was 28. 17%.Among them,the incidence rate of male was 13. 06%,while female was 15. 11%. There was no statistical difference betwe...