The quantity of Phenylsulfate(PhS) and Phenylglucuronide(PhG) excreted by rats after an oral dose of lm mol/Kg phenol was estimated and the following results were obtained. 1. Both PhS and PhG were almost completely excreted within 1 day. 2. The excretory quantity of PhS was greater than that of PhG. 3. High performance liquid chromatography, simplified the determination of PhS and PhG.