Anhydroglucitol in human plasma was studied by high pressure liquid chromatography, which was employed to simplify sampling procedures for the polyol assay and to avoid enzymatic treatment of the plasma for removal of glucose. Polyols in the column effluent were assayed by a flow fluorometric method, which involved two continuous successive reactions; periodate oxidation and the Hantzsch reaction. Plasma, 1 ml each, from 55 diabetic and 18 control subjects was deproteinized, concentrated, and subjected to the liquid chromatography. The results of this analysis indicated that the plasma anhydroglucitol level showed an inverse correlation with the plasma glucose level, while the correlation of glycerol and glucose levels was obscure.