Non-small-cell lung cancer usually carries a dismal prognosis. Novel treatment approaches are clearly warranted. Alexidine dihydrochloride is known as an antimicrobial mouthwash in preventing plaque and gingivitis. In recent study, alexidine dihydrochloride has also known an apoptosis-promoting anticancer activity. Autophagy is known as an important regulatory mediator for cell survival or death and its important role in cancer. However, the role of autophagy and its underlying molecular mechanisms in alexidine dihydrochloride treated lung cancer cell lines have not been clarifi ed. The purpose of this study are to determine whether alexidine induces autophagy and to fi nd out the its mechanism in alexidine-treated A549 cells, we performed MTT assay, western blotting, FACS (acridine orange, Annexin V/PI) by using autophagy inhibitors. Cell viability decreased in alexidine-treated cells according to dose dependent manner. Expression of LC3 II and Beclin 1 were increased in alexidine-treated cells according to dose dependent manner. These fi nding indicated that alexidine induced autophgy. LC3 expression after Beclin 1, ATG 5 and ATG 12 siRNA pre-treatment is markedly decreased in alexidine treated A549 cells. After SB203580, P38 MAP kinase inhibitor pre-treatment, the proportion of acridine orange stain-positive cells decreased in alexidine treated A549 cells. Our results indicated that p38 MAP kinase may be a key regulator for Beclin 1-dependent autophagy.