Phenolic compounds from Pueraria hirsuta L. grown in Georgia were studied. The leaves yielded the flavonoids robinin, nicotiphlorin, rutin, and the isoflavone glycoside daidsin; the roots yielded the isoflavones daidsin, daidsein, phormononetin, ononin, and the coumestan mirificoumestan. The dominant flavonoid in leaves was robinin, with contents of up to 1.7%. Dry extract of Pueraria hirsuta leaves containing the whole complex of biologically active compounds decreased urea, residual nitrogen, and creatinine levels in serum both in intact rats and in rats with acute renal failure induced by mercury dichloride. In terms of its hypoazotemic activity, the extract was as active as the therapeutic agent lespenephril. The functional state of the monooxygenase system of the cytoplasmic reticulum of kidney cells plays the defining role in the mechanism of the hypoazotemic action of the extract.