Abstract: The medicinal effect of the above-ground organs of Gynura divaricata was studied. It was showed that both the water extract (equal to 0.2 g/kg, 0.4 g/kg crude medicine) and 95% ethanol extract (equal to 0.2 g/kg and 0.4 g/kg crude medicine) of the fresh G. divaricata could significantly reduce blood sugar content of the healthy mice. The dosage of 0.4 g/kg crude medicine extracted by 95% ethanol had better effect on lowering the blood sugar content than 50 mg/kg glyburide. It was also indicated by experiments that both 40 g/kg crude medicine of ethyl acetate extract and 4 g/kg crude medicine of n-butanol extract of the dried Gynura divaricata plants had remarkable effect on lowering blood sugar content of normal mice, and 40 g/kg crude medicine of ethyl acetate extract could also remarkably lower blood sugar content of alloan-diabetic mice. The dosage levels of 32 mg/kg, 16 mg/kg and 8 mg/kg of total alkaloid, 8 mg/kg, 4 mg/kg and 2 mg/kg of total flavone, and 8 mg/kg,2 mg/kg of monomer compound IV (3-O-β-D-(6→1)glucopyranosyl -α-L-rhamnosyl kaemferol) extracted from G. divaricata demonstrated evident lowering effect on blood sugar content of both normal and alloan-diabetic mice. The effect was more significant to the alloan-diabetic mice, which started to effect at 0.5 h after having taken the extracts and lasted till 6.0 h to the alloan-diabetic mice, indicating that these extracts and monomer compound could work fast and have long-term effect on lowering the blood sugar content of the ill mice.