A simple, inexpensive, and efficient method for,separation and purification of the .alpha.- and .beta.-FORMS OF penta-O-galloyl-D-glucose (PGG) without the need for HPLC. The methods provided herein are useful for separating .alpha.-PGG or .beta.-PGG from a mixture that contains .alpha.-PGG and .beta.-PGG and other chemicals. The method for separation of .alpha.-PGG from a mixture of .alpha.-PGG and .beta.-PGG comprises the steps of adding water to a sample containing 50% or morec .alpha.-PGG and 50% or less .beta.-PGG; mixing the PGG and watcr to dissolve thc, PGG; filtering out any undissolvcd particles; and allowing the filtercd solution to stand undisturbcd until crystals form.