Biodegradation capacity of daidzein by intestinal microflora from thirty-two different animals were compared by High Performance Liquid Chromatography(HPLC).The results showed that all of the other thirty-one tested animals converted daidzein into O-desmethylangolensin(O-Dma) except the giant panda.Fourteen tested animals were detected with the ability to produce phytoestrogen equol with high physiological activities in their daidzein metabolites.The results indicated that different daidzein bioconverting capacity is influenced by genetic factors.Meanwhile,it is also related to some environmental factors like diet arrangement.Taken together,some special animals with strong daidzein biodegradation capacity,especially those ideal animals that can convert daidzein into equol efficiently,were determined by detecting daidzein metabolites produced in different animals.