Updated project metadata. Acetaminophen (APAP) is one of the most widely consumed and prescribed drugs. APAP overdose is one of the leading causes of intrinsic drug-induced liver injury (DILI), acute liver failure (ALF), and liver transplantation in the Western world. Mg2+, essential for health, plays a role in virtually every process within the human cell. The cellular transporter family cyclin M, also known as CNNM, plays a key role in Mg2+ transport across the cell membranes in different organs. Here, we identified that the expression of CNNM4 is elevated in the liver of patients with APAP-induced liver injury (AILI), with a concomitant disturbance in serum Mg2+ levels. We demonstrated that, in the liver, APAP interferes with the Mg2+ mitochondrial reservoir via CNNM4, which affects ATP production and ROS generation, further boosting endoplasmic reticulum (ER) stress of the hepatocytes. Importantly, the CNNM4 mutant T495I showed no effect. Finally, a shift in localization of CNNM4 from membrane to ER was shown under APAP toxicity. Therapeutic targeting of Cnnm4 in the liver with nanoparticles and GalNAc-formulated siRNA provides efficient protection from AILI by restoring hepatocyte Mg2+ homeostasis and by inducing hepatocyte restoration. Our results suggest that inhibition of Cnnm4 may represent an alternative route for the treatment of DILI..