Abstract: OBJECTIVE To investigate into the screening of the active components of Plumula Nelumbinis Nuciferae. METHOD Extraction and isolation were performed on Plumula Nelumbinis Nuciferae to obtain 70% alcohol extract, total alkaloids and total flavonoids, which were then used in diabetes mice models made with alloxan to observe their effect in increasing the blood sugar of mice. RESULT Antagonizing effect against the increase of blood sugar was found in the alcohol extraction group and total alkaloids group, with marked significance ( P < 0.05; P < 0.01) . No marked effect was detected in the total flavonoids group ( P > 0.05 ). CONCLUSION The active components in Plumula Nelumbinis Nuciferae for lowering blood sugar are alkaloids, not flavonoids.