Stereochemical structure of a 2:2 complex of (-)-epigallocatechin 3-gallate (EGCg) and caffeine, which was the main content of a crude precipitate formed by creaming, was determined by X-ray crystallographic analysis, and intermolecular interactions forming between EGCg and caffeine moieties were elucidated. Stereochemical structure and intermolecular interactions of a 2:2 complex of EGCg and nicotinamide was also determined.