Serial determinations of serum C-reactive protein are helpful in the detection and monitoring of postoperative complications associated with inflammation and/or tissue necrosis. The serum C-reactive protein level begins to increase within six hours after operation, peaks on the second day, and by the third postoperative day begins to decrease toward the preoperative level. In cases with surgical complications involving inflammation, serum C-reactive protein levels remain elevated and do not show a decline on the third postoperative day. Serum levels of other “acute-phase proteins,” such as alpha-1 acid glycoprotein, ceruloplasmin, alpha-1 antitrypsin, and haptoglobin, were found to increase in response to surgical procedures, but subsequent to the increase in C-reactive protein. These other proteins offer no additional information in monitoring the postoperative acutephase response.