Objective: To investigate the effects of Rehmanniae Radix and Rehmanniae Radix Praeparata on blood glucose and blood lipid in streptozocin-induced diabetic mice. Method: C57 male mice was administrated by intraperitoneal injection of STZ(60 mg ·kg-1) to establish diabetes model. Fresh Rehmannia root of 6

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2 g ·kg-1 and prepared Rehmannia root of the same doses were ig administrated in grouped mice respectively once daily for a week. The effects on blood glucose and blood lipid in diabetic mice were observed accordingly. Result: Fresh Rehmannia root of 6 g ·kg-1 could reduce blood glucose and improve blood lipid in the diabetic mice

compared with the mode group P<0.01.Fresh Rehmannia root of 4 g ·kg-1 and prepared Rehmannia root of 6 g ·kg-1 could reduce blood glucose

and compared with the mode group P<0.05.Fresh Rehmannia root and prepared Rehmannia root showed effects of reducing blood glucose and improving blood lipid in the diabetic mice with dose-effect manner. Conclusion: Fresh Rehmannia root is better for hypoglycemic effect and improving blood lipid in streptozotocin-induced diabetic mice than prepared Rehmannia root.