Introduction: Hyperlipidemia refers to a group of lipid metabolism disorders characterized by increased levels of total cholesterol, triglyceride, and/or lowdensity lipoprotein cholesterol and/or decreased levels of high-density lipoprotein cholesterol. This study aims to investigate the effects of Lactobacillus on lipid metabolism and hepatic steatosis in male mice fed with a high-fat diet by measuring blood lipid, hepatic function and hepatocyte morphology. Material and methods: Eighty male Institute of Cancer Research (ICR) mice were fed with a high-fat diet for 6 weeks to establish hyperlipidemic models. Then, mice were treated with a high or low concentration of Lactobacillus of human source, mouse source, or plant source, respectively. Results: After 3 weeks of therapy, except for the human Lactobacillus treatment group, the blood cholesterol, triglyceride and low-density lipoprotein cholesterol in mice treated with Lactobacillus of mouse and plant source were lower than those in the hyperlipidemic model group. After 4 weeks of treatment, the levels of blood biochemical indexes in mice in all treatment groups were significantly different, when compared to those in the hyperlipidemic model group. Conclusions: Lactobacillus may regulate blood lipid in mice fed with a highfat diet. Lactobacillus can improve the high cholesterol, high blood lipid, and injury of hepatic function, and prevent further development of atherosclerosis caused by a high-fat diet to some extent. Correct dietary structure is the basis for the treatment of dietary hyperlipidemia and its complications. [ABSTRACT FROM AUTHOR]