The purpose of this study was to investigate the effects of a dietary intake of Prunella vulgaris var. lilacina Nakai ethanol extract (PVE) on lipid metabolism and fibrosis in the liver tissue of diet-induced obese mice. Prunella vulgaris var. lilacina Nakai (PV) is a perennial herbaceous plant belonging to the Labiatae (Lamiaceae) family and is a natural material that has been reported to have antioxidant and anti-cancer effects. C57BL/6J mice were divided into 3 groups and fed a normal diet, a high-fat diet (HFD), or a high fat + 1% PVE (w/w) diet for 12 weeks. In hematoxylin & eosin (H&E) stained liver tissues, the HFD group showed an increase in the number and size of lipid droplets, but these were rarely observed in the PVE fed mice. The hepatic lipotoxicity markers, plasma glutamic oxaloacetic transaminase (GOT), and glutamic pyruvic transaminase (GPT) levels were elevated owing to the high-fat diet intake but plasma GPT levels showed a significant decrease on supplementation with the PVE. Moreover, the PVE improved adiponectin dysregulation, and reduced blood glucose imbalance due to insulin resistance, thereby inhibiting fibrosis of the liver and adipose tissue. The PVE caused an excretion of lipids from the body as feces, thereby lowering the lipid content in the liver tissue and increasing the accumulation of hepatic proteins, thus contributing to improvement in liver health. Our findings highlight the potential of the dietary effects of the PVE in the prevention of hepatic lipotoxicity and fibrosis.