The nicotinamide adenine dinucleotide phosphate oxidase (NOX) enzyme complexes are the primary sources of endogenous ROS.[qv: 29,30] Especially, NOX4, a nonphagocytic NOX homolog which can generate ROS and activate HSCs, has been found to play a prominent role in liver fibrosis.[qv: 31] Herein, we demonstrated that PD‐MC potently down‐regulated NOX4 in LPS‐activated LX‐2 cells and primary fibrotic HSCs, which highly supported the potential NOX4 based mechanism for the ROS scavenging by PD‐MC (Figure 3E; Figure S10D,E, Supporting Information). The gene discussed is NOX4; the disease is Hepatic fibrosis.