Dry ethyl acetate extract containing flavonoids was obtained from above-ground parts of Astragalus corniculatus Bieb. Seven flavonoids were isolated and identified as rutin, hyperoside, isoquercitrin, narcissin, quercetin, kaempferol and isorhamnetin for the first time. The extract was found to be practically non-toxic (acute oral toxicity > 5 g kg(-1) in mice). The extract was investigated for antihypoxic activity in two models of experimental hypoxia--haemic and circulatory. Antihypoxic activity was especially pronounced in the model of circulatory hypoxia. This effect may be attributed, at least in part, to the presence of flavonoids in the extract.