In vitro and in vivo efficacy studies and clinical trials have shown that EC-18 has a mode of action of improving neutropenia by promoting neutrophil production from hematopoietic stem cells and at the same time, efficiently controlling STAT6/Complement 3(C 3), suggesting its potential to be developed as an orally administered new drug for treatment of neutropenia resulting from decreased neutrophils caused by administration of an anticancer agent.