Changes in functional ceruloplasmin (Cp) concentrations of plasma and exudate during acute and chronic inflammatory processes were studied in detail by measuring Cp oxidase activity in the carrageenin-induced inflammation in rats. In contrast with the plasma functional Cp level as an acute-phase reactant, the exudate functional Cp level was very low during the acute phase, increased in the chronic phase and reached a constant value which was only half value of the plasma functional Cp level. The locally injected Cp had no effect on the carrageenin-induced inflammation, suggesting that exogenous Cp has no anti-inflammatory effect on the inflamed rats eating normal diet.