OBJECTIVE To investigate the protective effect and possible mechanism of Chaihu Shugan Granules on acute liver injury in mice. METHODS Chaihu Shugan Granules was administered to mice at low, medium and high dosages (crude drug dose: 11.4, 22.8, 45.6 g·kg^-1) continuously for 7 d. Two hours after the last administration, the animal model was made with 0.2% tetrachloromethane (CCl₄) solution except the control group. The serum and liver tissues were collected after 12 h. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and superoxide dismutase (SOD), malondialdehyde (MDA), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and reactive oxygen species (ROS) in liver tissues were measured by ELISA. HE staining was conducted to reveal the histopathological changes in liver. Transcriptomics was used to obtain differentially expressed mRNA in liver tissues and enrich differentially expressed pathways, while metabolomics was used to obtain changes in liver endogenous metabolites and enriches pathways of differential metabolites using KEGG database. The expression and location of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MARK), kelch-like ECH-associated protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in liver tissues were measured by immunohistochemistry and Western blot. RESULTS Compared with the model group, the serum levels of ALT, AST and MDA, IL-6, TNF-α and ROS in liver tissues of mice in each group of Chaihu Shugan Granules decreased significantly (P<0.05 or P<0.01), while the level of SOD in liver tissues increased significantly (P<0.01). The degree of necrosis and inflammatory infiltration in liver cells decreased significantly. Nqo1 gene and NAD(P)H: quinone oxidoreductase 1 (NQO1) expression were up-regulated while Ccl2 gene and monocyte chemotactic protein 1 (MCP-1) expression were down-regulated. Organic acids were significantly down-regulated and carbohydrate was significantly up-regulated, the expressions of JNK, p38 MARK and Keap1 in liver tissues were significantly decreased (P<0.05 or P<0.01), while the expressions of Nrf2 and HO-1 were significantly increased (P<0.01). CONCLUSION Chaihu Shugan Granules might have protective effect on CCl₄-induced acute liver injury in mice by activating the Keap1-Nrf2/HO-1 signal pathway.