Continuing researches on the monitoring of acute phase proteins (A.P.P.) as markers of septic risk in the surgery patient, a series of 50 patients suffering from pathological processes classifiable as follows has been examined: 1) acute biliary pancreatitis 18 cases; 2) acute hepatobiliary pathology without pancreatic impairment 26 cases; 3) burn 2 cases; 4) particularly serious sepsis in immunodepressed subjects 4 cases. The constant finding of increased values of PCR, fibrin, cerul, alpha 1-Trip in the surgery patient at septic risk and their normalisation after treatment is, in single cases, particularly significant and perfectly consistent with the clinical entity of the infectious process. In immunodepressed surgery patients showing deficiency in nitrogen balance and suffering from endotoxin shock a marked, persistent decrease in alpha 2-Macro, Tranfs, Albu and Prealbu parameters was noted. The reduction in these four A.P.P. can, in the Authors' experience, be considered a diagnostic indicator of sepsis of extreme gravity and an unfavourable prognosis finding regarding the course of the disease process.