It has been suspected that beer drinking may change the hormonal status of men caused byphytoestrogens. Five different Austrian lager beers have been investigated for estrogenic activityby a yeast two-plasmid system harboring the human estrogen receptor α, after concentration bysolid phase extraction. The beer concentrate was further fractionated by reversed phase HPLC,and then the fractions were characterized by the biological assay and GC-MS. The most potentfraction did not contain a known phytoestrogen. The total activity corresponded to an average of 43ng of 17β-estradiol/L of beer. It was concluded that the human health hazard of beer drinkingoriginating from compounds activity on the estrogen receptor α is negligible. Keywords: Phytoestrogens; beer; yeast; isoflavonoids