Green tea catechins have recently gained significant acceptance as a cancer preventive, and one of the important features of catechins is their interactions with various target molecules. We recently found a functional and structural similarity between catechins and chaperones: Stochastic conformational analysis in silico revealed numerous conformations of (-)-epigallocatechin gallate, (-)-epicatechin gallate and (-)-epigallocatechin, showing a unique flexibility and mobility of the catechin molecules and suggesting the significance of a galloyl group in conformational variation. Since these conformations result in interaction with various types of molecules, we think that green tea catechin induces cancer preventive activity mediated through a chaperone-like property.