Objective: To study the effects of Portulaca oler acea, a Chinese medicinal herb, on insulin resistance in rats with type 2 diabet es mellitus (T2DM). Methods: Experimental model of T2DM was established by injection of streptozotocin (25mg/kg) and feeding with high calorie forage. The effects o f Portulaca oleracea on oral glucose tolerance, serum levels of insulin, triglyc eride, total cholesterol, high density lipoproteins cholesterol and free f atty acids, and insulin sensitivity index were all observed. Results: Portulaca oleracea could reduce the body weight, improve the impaired glucose tolerance and lipid metabolism, decrease serum free fatty acids, attenuate hyperinsulinemia and elevate insulin sensitivity. Conclusion: Portulaca oleracea could improve insulin resistance i n rats with T2DM, and the mechanism might be related to its actions in improving lipid metabolism and decreasing free fatty acids. Objective: To study the effects of Portulaca oler acea, a Chinese medicinal herb, on insulin resistance in rats with type 2 diabet es mellitus (T2DM). Methods: Experimental model of T2DM was established by injection of streptozotocin (25 mg / kg) and feeding with high calorie forage. The effects of Portulaca oleracea on oral glucose tolerance, serum levels of insulin, triglyc eride, total cholesterol, high density lipoproteins cholesterol and free f atty acids, and insulin sensitivity index were all observed. the body weight, improve the impaired glucose tolerance and lipid metabolism, decrease serum free fatty acids, attenuate hyperinsulinemia and elevate insulin sensitivity. Conclusion: Portulaca oleracea could improve insulin resistance in rats with T2DM, and the mechanism might be related to its actions in improving lipid metabolism and decreasing free fatty acids.