The diphtheria carrier problem and its importance in children is discussed. Non-penicillin therapy of diphtheria carriers is briefly reviewed and commented upon. Literature on penicillin therapy in the diphtheria carriers is reviewed. An analysis of the results of 70 cases of diphtheria carriers treated by different forms of penicillin therapy is presented and commented upon, especially in regard to the correlation between the effectiveness of the therapy and the pathology of the nose and throat. Rational treatment of diphtheria carriers is suggested in the conclusion of the paper.