A method for preparing mixture powders of platycodon grandiflorus and momordica charantia includes washing at least one year-old platycodon grandiflorus, and momordica charantia wherein the platycodon grandiflorus includes stem, root, and leaf portions thereof cutting the washed platycodon grandiflorus and momordica charantia hot air-drying the cut platycodon grandiflorus and momordica charantia in a dryer at a temperature exceeding a boiling point of hydrogen cyanide gas to remove hydrogen cyanide therefrom pulverizing the cut and dried platycodon grandiflorus and momordica charantia to prepare platycodon grandiflorus powders and momordica charantia powders and mixing the platycodon grandiflorus powders and momordica charantia powders to produce the mixture powders of platycodon grandiflorus and momordica charantia.