Objective：To study the effect of oleuropein in combination of acrolein on proliferation and apoptosis related to endoplasmic reticulum stress(ERS) in human bronchial epithelial cells. Methods：HBE cells were treated with oleuropein and acrolein. MTT assay was performed to detect cell viability. Plate clone formation assay was used to get colony forming efficiency. Hoechst 33258 staining and flow cytometric assay were applied to investigate the apoptosis of cells. The levels of ERS biomarkers including glucose-regulated protein 78(GRP78) and C/EBP homologous protein(CHOP) were measured by Western blot. The mRNA expressions of GRP78 and CHOP were analyzed by real-time PCR. Twelve male Sprague-Dawley rats were treated with acrolein alone through intraperitoneal injection, or olive leaf extract in combination through gavage. Lung tissues were obtained from the rats for detecting the expressions of GRP78 and CHOP. Results：HBE cell proliferation was inhibited by acrolein in a dose dependent manner. Cell prolife-