Arsenic trioxide (ATO)‑induced hepatotoxicity limits the therapeutic effect of acute myelogenous leukemia treatment. Magnesium isoglycyrrhizinate (MgIG) is a natural compound extracted from licorice and a hepatoprotective drug used in liver injury. It exhibits anti‑oxidant, anti‑inflammatory and anti‑apoptotic properties. The aim of the present study was to identify the protective action and underlying mechanism of MgIG against ATO‑induced hepatotoxicity. A total of 50 mice were randomly divided into five groups (n=10/group): Control; ATO; MgIG and high‑ and low‑dose MgIG + ATO. Following continuous administration of ATO for 7 days, the relative weight of the liver, liver enzyme, histological data, antioxidant enzymes, pro‑inflammatory cytokines, cell apoptosis and changes in Kelch‑like ECH‑associated protein 1/nuclear factor erythroid 2‑related factor 2 (Keap1‑Nrf2) signaling pathway were observed. MgIG decreased liver injury, decreased the liver weight and liver index, inhibited oxidative stress and decreased the activity of glutathione, superoxide dismutase and catalase, production of reactive oxygen species and levels of pro‑inflammatory cytokines, including IL‑1β, IL‑6 and TNF‑α. Western blotting showed a decrease in Bax and caspase‑3. There was decreased cleaved caspase‑3 expression and increased Bcl‑2 expression. MgIG notably activated ATO‑mediated expression of Keap1 and Nrf2 in liver tissue. MgIG administration was an effective treatment to protect the liver from ATO‑induced toxicity. MgIG maintained the level of Nrf2 in the liver and protected the antioxidative defense system to attenuate oxidative stress and prevent ATO‑induced liver injury.