Our previous results demonstrated that silibinin induced autophagic and apoptotic cell death dependent on reactive oxygen species (ROS especially H(2)O(2) and [image omitted] ) in HT1080 cells. In this study, we further show that p38-NF-κB pathway is involved in silibinin-induced ROS-mediated autophagy. Cells were pretreated with serum-free media for 24 h before being treated with silibinin. Generation of ROS and autophagy was detected in 15 min and 1 h, respectively. Development of autophagy was supported by an upregulated expression of Beclin-1 and conversion of light chain (LC3-I-LC3-II). Expression of p38/p-p38 and transposition of NF-κB from cytoplasm to nuclei were also increased. Inhibitors of p38 and NF-κB and scavengers of H(2)O(2) and O(2)(*-) reduced both generation of ROS and simultaneous occurrence of silibinin-induced autophagy. Besides, expression of p38/p-p38 and transposition of NF-κB from cytoplasm to nuclei were decreased by these two ROS scavengers. ROS and p38-NF-κB pathway were possibly cooperated in a positive feedback mechanism. Inhibition of p38, NF-κB, H(2)O(2), or O(2)(*-) rescued cells from silibinin-induced death in a long-term (12 h) manner. According to the previous study that silibinin-induced autophagy was a positive regulator of apoptotic cell death, it was possible that ROS and p38-NF-κB mediated silibinin-induced autophagy and eventually led to cell death.