An investigation was made to evaluate the therapeutic potential of the total polyphenolic acids fraction (PAF) from Salvia miltiorrhiza Bunge in the type 2 diabetes mellitus rats model with an oral dose of 187 mg/kg for 28 days. The results showed that PAF induced a significant decrease in fasting blood glucose (FBG), fasting blood insulin (FINS), total cholesterol (TC), triglyceride (TG) and blood urea nitrogen (BUN), and an obvious increase in insulin sensitivity index (ISI) in diabetic rats induced by a high fat diet and a low dose of streptozocin (STZ). These results suggested that PAF has antidiabetic potential in vivo. Copyright © 2011 John Wiley & Sons, Ltd.