Our data revealed that (I) artesunate targeted mitochondria to mediate mitochondrial dysfunction and resulted in mitochondrial ROS production; (II) due to excessive mitochondrial ROS, artesunate inhibited CRC growth by inducing p16- and p21-dependent cell senescence and caused cell cycle arrest but not by promoting cell apoptosis; (III) artesunate overactivated autophagy in an ROS-dependent manner to inhibit cell viability; and (IV) artesunate activated IRE1α signaling to cope with senescence-related ER stress. This evidence concerns the gene ERN1 and colorectal carcinoma.