Gynura divaricata (L.) DC and G. bicolor DC are used as secret recipes to treat diabetes mellitus in some parts of China. Pharmacological tests were performed to prove the anti-hyperglycemic effect of these two plants of genus Gynura Cass. in this study. Both water and 95% ethanol extracts of fresh G. divaricata had significant effects on lowering blood glucose level in normal mice, in which the dose of 0.4 g (crude drug)/kg of 95% ethanol extract was more effective than 50 mg/kg glyburide. The ethyl acetate and n-butanol extracts of dried G. divaricata had significant effects on lowering blood glucose level in normal and alloxan diabetic mice too. Both ethyl acetate and n-butanol extracts of dried G. bicolor showed very significant effect on lowering blood glucose level to normal and alloxan-diabetic mice, and the dose 4.0 g (crude drug)/kg had a more hypoglycemic effect than 50 mg/kg glyburide in normal mice.