The present study aimed to investigate the effects of administering Platycladus orientalis leaf (POL) extract on biomarkers related to glucose and lipid metabolism, liver function, and inflammation in an adult animal model. A freeze-dried ethanol extract was prepared using POLs. In a 24-week experiment on 24-week-old Sprague Dawley male rats, animals (n=10) were administered 12 mg/kg/d of POL extract dissolved in saline; control rats (n=9) were administered saline. All rats had access to chow and tap water ad libitum. Blood levels of glucose, insulin, adiponectin, total cholesterol, high-density lipoprotein cholesterol, triglyceride, liver function biomarkers, and inflammatory parameters were assayed and compared. Experimental rats had higher adiponectin levels (P<0.05) and lower fasting glucose levels (P=0.06) than controls. In experimental rats, adiponectin levels were inversely correlated with blood concentrations of insulin, triglyceride, aspartate aminotransferase, and interleukin-1β (P<0.05) after controlling for weight and fasting glucose levels. These findings indicate that POL extract administration may improve glucose and lipid metabolism by elevating blood adiponectin levels, which are known to reflect insulin sensitivity in liver. This study shows POL extracts have anti-diabetic properties and suggests their utilization as a functional food ingredient.