‘IT0STUDY PROTEIN METABOLISM with special reference to tyrosine as well as to study the deranged metabolism of aromatic compounds in phenylketonuria and similar disorders, quantitative determination of urinary phenols is desirable. Volterra (1) measured three phenolic fractions in the urine by distillation. Phenols have been measured quantitatively after ethyl acetate extraction by Bray and Thorpe (2) and after ether extraction by Rogers et a!. (3). A previous report described a method of ether extraction of urine for free, acid, and conjugated phenols (4). A modification of this now offers a rapid method for both quantitative determination of urinary phenols and preparation of phenols for chromatography.