Dehydrocostuslactone (73) is a sesquiterpene lactone isolated from the Saussurea lappa and Aucklandia lappa. Dehydrocostuslactone (73) triggers ER stress via EIF2AK3-DDIT3 and ERN1-MAPK/JNK signaling pathways in human NSCLC A549 and NCI-H460 cell lines, through induction of ROS in the cytoplasm. The gene discussed is DDIT3; the disease is non-small cell lung carcinoma.