Carbon-14-labeled plasma proteins given by mouth to dogs with sterile abscesses undergo decreased absorption, presumably owing to impaired digestion of protein. The turnover of plasma albumin is greatly accelerated but the globulins, excluding fibrinogen, show little change during the acute stage of the sterile inflammation. Fibrinogen shows very rapid production and utilization during acute inflammation. Large amounts of C14 are incorporated in fibrinogen within a few hours after ingestion of the labeled material. The labeled fibrinogen largely disappears within 2 to 4 days after its production. The appearance of C14 in new red cells from labeled protein or amino acid sources is reduced by inflammation—evidence of impaired synthesis. The pus of the sterile abscess contains a good deal of C14 activity which at times is as much as that found in the liver. Pus cell C14 activity per milliliter is similar after injection of labeled plasma and ingestion of labeled plasma or lysine. However, the pus cell fraction contains 3 to 4 times more C14 activity per milliliter than does the supernatant fluid when the isotope is fed. In the supernatant fluid the activity is all within precipitable protein, much of which is probably derived from the blood plasma. In spite of increased loss of C14 as CO2 in the expired air and in the pus, there is evidence of conservation of protein-building materials for maintenance of new plasma proteins and tissue proteins in the more active organs (e.g. liver)—a shift of protein C14 from the less active tissues (muscle and skin).