This review article explores the role of lactate and lactate metabolism in liver diseases, including liver fibrosis, non-alcoholic fatty liver disease (NAFLD), acute liver failure (ALF), and hepatocellular carcinoma (HCC). Lactate, initially considered a metabolic waste product, is now recognized as a signaling molecule and a substrate for energy production. The liver plays a crucial role in glucose, fatty acid, and lipid metabolism, immune response, and cytokine secretion. Abnormalities in lactate and lactate metabolism can lead to liver diseases, and lactate-related genes can predict disease prognosis. Targeting lactate production, transport, and lactylation may be potential therapeutic approaches. The article discusses the mechanisms by which lactate and lactate metabolism contribute to liver diseases, such as the activation of hepatic stellate cells (HSCs) in liver fibrosis, the role of hexokinase 2 (HK2) in NAFLD, and the promotion of tumor progression in HCC. Additionally, the article highlights the potential of lactate and lactate metabolism-related genes (LMRGs) as biomarkers and therapeutic targets. Overall, the review emphasizes the importance of lactate and lactate metabolism in liver diseases and suggests that further research is needed to develop effective treatments.This review article explores the role of lactate and lactate metabolism in liver diseases, including liver fibrosis, non-alcoholic fatty liver disease (NAFLD), acute liver failure (ALF), and hepatocellular carcinoma (HCC). Lactate, initially considered a metabolic waste product, is now recognized as a signaling molecule and a substrate for energy production. The liver plays a crucial role in glucose, fatty acid, and lipid metabolism, immune response, and cytokine secretion. Abnormalities in lactate and lactate metabolism can lead to liver diseases, and lactate-related genes can predict disease prognosis. Targeting lactate production, transport, and lactylation may be potential therapeutic approaches. The article discusses the mechanisms by which lactate and lactate metabolism contribute to liver diseases, such as the activation of hepatic stellate cells (HSCs) in liver fibrosis, the role of hexokinase 2 (HK2) in NAFLD, and the promotion of tumor progression in HCC. Additionally, the article highlights the potential of lactate and lactate metabolism-related genes (LMRGs) as biomarkers and therapeutic targets. Overall, the review emphasizes the importance of lactate and lactate metabolism in liver diseases and suggests that further research is needed to develop effective treatments.