The invention provides an orally taken medicine for reducing blood sugar. The orally taken medicine is prepared from Radix Astragali, Herba Leonuri, wolfberry fruit, Polygonatum odoratum, Dickinsia hydrocotyloides Franch, semen cuscutae, cassia twig, white peony root, pulp of Fructus Mume, areca nut shells, Rhizoma Alismatis, Cortex Lycii, Lonicera japonica, corn silk, Radix Puerariae, starwort root, aconite root, Euphorbia pekinensis Rupr. and Daphne genkwa Sieb. et Zucc.. A preparation method of the orally taken medicine comprises the following steps: crushing raw materials, adding water and yeast, fermenting the raw materials at 35-38 DEG C for 5-10 d, filtering the fermented raw materials, adding water to filter residues, decocting the filter residues, mixing above obtained two filtrates, heating the obtained filtrate mixture, adding modified starch and sodium caseinate, and carrying out spray drying to obtain the orally taken medicine. The orally taken medicine for reducing blood sugar has the advantages of small toxic and side effects, fast effect and good curative effect.