The water extract of pilose antler of Cervus nippon var. mantchuricus (WEC) was investigated in respect of its effect on ceruloplasmin and $alpha$$_1$-cysteine protease inhibitor (CPI), which are acute-phase proteins showing increased synthesis following inflammatory stimulus in rat. Ceruloplasmin and CPI were spectrophotometrically determined by the oxidase activity and the inhibitory activity on papain, respectively, and their changes in the concentrations in plasma or serum were examined after oral administration of 0.04% WEC to rats during 7 days following inflammation by subcutaneous injection of turpentine oil or lipopolysaccharide (LPS). WEC suppressed the maximum increases in ceruloplasmin and CPI on the 4th day after injection of turpentine oil, but the suppression in ceruloplasmin was more potent than that in CPI. On inflammation by LPS the suppression of the maximum increase in ceruloplasmin by WEC was found on the 2nd day, but the result was less significant from that obtained by the treatment with turpentine oil. Administration of WEC for at least 4 days was required to suppress the maximum increase in ceruloplasmin due to inflammation by turpentine oil. When WEC was administered to rats after injection of turpentine oil, a high dosage (0.36% of WEC) was requisite for the suppression on the maximum increase in ceruloplasmin.