A simple, inexpensive, and efficient method for separation and purification of the α-and β-forms of penta-O-galloyl-D-glucose (PGG) without the need for HPLC. The methods provided herein are useful for separation α-PGG or β-PGG from a mixture containing α-PGG and β-PGG and other chemicals. The method for separation of α-PGG from a mixture of α-PGG and β-PGG comprises the steps of: adding water to a sample containing 50% or more α-PGG and 50% or less β-PGG; mixing the PGG and water to dissolve the PGG; filtering out any undissolved particles; and allowing the filtered solution to stand undisturbed until crystals form.